A perfectionist is defined as follows:

a person who refuses to accept any standard short of perfection.

But I am looking for a noun which describes a person who refuses to move forward in an activity or thought unless the present one is sorted out. Kind of like having a mental block to move ahead, but by choice.


14 Answers 14


It's not listed in the major dictionaries, but Wiktionary mentions completionist:

One who insists on completion.

I wouldn't count on your audience knowing exactly what it means, so you might have to explain it first, but you probably wouldn't get any closer with a single word.

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    Insisting on completion doesn't necessarily mean insisting on completion of one task before moving on to another, only that the task must be completed. IMO anyway. I've heard the term in the context of gaming, and one would never think a completionist would have to finish one game before starting the next. – nasch Jul 9 '19 at 17:49
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    I've only heard completionist in the context of a collector who wants to own "one of everything". – Marthaª Jul 9 '19 at 20:05
  • @nasch: By semantical definition, I agree with your distinction. But considering its practical usage in reference to gamers, the distinction does not exist. "Completionist" is even used (loosely and not pedanctically correctly) for people who keep playing a game longer than the speaker would. – Flater Jul 11 '19 at 9:09
  • @Flater, eep - I commented on the wrong answer. I’ve moved it to BB On’s answer where it makes much more sense! Thanks. – Beejamin Jul 11 '19 at 14:08
  • @Flater What do you mean by the distinction does not exist? If you mean there isn't a word for someone who completely finishes one game before starting the next, I agree. – nasch Jul 11 '19 at 16:24

I would use single-minded (Merriam)

: having one driving purpose or resolve : DETERMINED, DEDICATED

or unitasker (wiktionary)

A person who does a single thing at a time.

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    See also "methodical" or "single minded". – The Nate Jul 10 '19 at 5:28
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    Or “one track mind.” – mxyzplk Jul 11 '19 at 13:13
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    Unitasker is great. I use monotasking in a similar way, and have anecdotally heard it more than unitasking. – Beejamin Jul 11 '19 at 14:06
  • This does not say why your answer is right. It has no explanation. It has no original content. Please edit this answer to amend these deficiencies. – tchrist Jul 12 '19 at 21:07
  • How does one "explain" how this is correct? That the word matches the definition is self-evident. – BB ON Jul 12 '19 at 21:14

Single-threaded (a term borrowed from computer science)

In computer programming, single-threading is the processing of one command at a time. The opposite of single-threading is multithreading. Thread (computing) - Wikipedia https://en.wikipedia.org/wiki/Thread_(computing)

"He had a single-threaded mind"

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    I have never heard of someone having a "single-threaded mind", but I have heard of them having a "one-track mind"... – Chronocidal Jul 10 '19 at 14:10
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    "Multi-tasker" is in common use for a person who can chop and change between activities on a frequent basis without his/her productivity suffering. I think calling somebody a "single-tasker" would be understood, though I've not heard it in use. (It might cause hurt or offence). These terms are also borrowed from computer science. – nigel222 Jul 11 '19 at 8:43

Serialist could have something of the meaning you want. The problem is that it has some specific meanings in other contexts, and doesn't seem to have been used in relation to the completion of tasks. The closest meaning in the OED is meaning #4, but it relates more to learning rather than the completion of tasks.

  1. A person who writes stories, novels, etc., for publication in serial form.

  2. Philosophy. A believer in or advocate of a theory based on the analysis of the self as a series or succession of states or events. rare.

  3. Music. A composer, advocate, or admirer of serial music or composition.

  4. Psychology. A person who tends to acquire knowledge about something by consideration of a series or sequence of items, facts, etc., in turn.

Examples given for meaning 4 are:

"Serialists learn, remember and recapitulate a body of information in small, well-defined and sequentially-ordered segments."

"Operation learning is the style of those who are routine serialists; comprehension learning that of routine holists."

More broadly, you could say that such a person is "stubbornly serial" or "doggedly serial" in completing their tasks, though you'd probably have to add a subordinate clause explaining what you mean.


You could use Linear, according to Merriam Webster Dictionary:

of, relating to, or based or depending on sequential development

  • I'm not sure that if you described someone as "linear", I would assume that you meant they would refuse to move to the next activity until their current one was completed. – KillingTime Jul 9 '19 at 18:30
  • What would you assume about their work habits? – Delwit Noison Jul 9 '19 at 18:33
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    The term "sequential" (used in the above definition of linear) is another good choice to describe a linear method of working. – Syntax Junkie Jul 10 '19 at 19:55
  • This does not say why your answer is right. It has no explanation. It has no original content. Please edit this answer to amend these deficiencies. – tchrist Jul 12 '19 at 21:06

Sticktoitiveness (Grammarist):

Sticktoitiveness — meaning dogged perseverance — regularly appears in three forms: the unhyphenated form, stick-to-it-iveness, and stick-to-itiveness. The three-hyphened form was most common when the word came about in the U.S. in the late 19th century (as attested by the OED‘s examples and in historical news searches). But today, the two-hyphened stick-to-itiveness is most common, and the unhyphenated form is still comparatively rare. The last form is steadily gaining ground, though, and is likely to prevail in the near future, if the word stays in the language.

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    Thanks for the fine example of the evolution of solidification in hyphenated words. I'm not sure how often I'll use the word in actual speech, though. – Edwin Ashworth Jul 9 '19 at 11:36
  • @EdwinAshworth - I've heard the word used a number of times in actual speech (not so much since I retired, though). Not sure I've ever seen it in print prior to looking it up, though. – Hot Licks Jul 9 '19 at 11:47
  • It's probably too big a risk when you've misplaced your article giving the correct hyphenation/s. (I really struggled to find where to paste the article in a document I knew I had on 'the trend towards solidification over time of compound nouns, the rate generally being faster in the States'. I suppose I had to stick to it before I could paste it.) – Edwin Ashworth Jul 9 '19 at 12:22
  • Thanks for the answer. If am not wrong it's an adjective, right ? – Rahul Jul 9 '19 at 12:44
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    @Rahul, I’d say noun because it ends "-ness" like sadness and prettiness (those are both nouns in thefreedictionary.com). For example, sometimes I suffer from a certain sadness/prettiness... – Pam Jul 9 '19 at 18:22

If the behavior is particularly extreme or obsessive, you might call them monomaniacal. According to Merriam-Webster:

monomania: excessive concentration on a single object or idea

  • I do not know who nominated this for deletion, but looks OK to me. – Cascabel Jul 12 '19 at 22:27

You could say that someone is "mired" in a task - a mire is like a swamp or bog, so it's a metaphor for being stuck in something. This doesn't necessarily mean that they wouldn't like to leave it and do something else, but it may often be the case that they are refusing to move on.

  • Thanks for the answer. I am actually looking for a noun. What you suggested is a verb. I might use it too. – Rahul Jul 9 '19 at 12:39
  • Is this a good usage ? Sometimes I get mired in my thoughts. – Rahul Jul 9 '19 at 12:39
  • Yes, that works I think. – Max Williams Jul 9 '19 at 16:07

First word that came to mind is persistent (from Wiktionary, 2019):

Obstinately refusing to give up or let go.

This means that when someone is engaging in a task there is a reluctance to let go of performing the task, even when not appropriate anymore.

From Cohen & Levesque (1990):

It does not seem unreasonable to require that a robot not procrastinate forever. Moreover, we surely would want a robot to be persistent in pursuing its goals, but not fanatically so. Furthermore, we would want a robot to drop goals given to it by other agents when it determines the goals need not be achieved.

  • Persistent does not imply to the exclusion of other tasks – MSalters Jul 12 '19 at 11:55
  • This does not say why your answer is right. It has no explanation. It has no original content. Please edit this answer to amend these deficiencies. – tchrist Jul 12 '19 at 21:06

Some personality tests use the term completer-finisher alternatively just completer or finisher. An example personality test is Myers Briggs, although some other personality tests use these terms too. A completer-finisher goes the extra mile to make sure that everything is just right and can frustrate their team mates at work by wanting to get everything done exactly right before moving on to the next task.



Google dictionary (for fixate):

cause (someone) to acquire an obsessive attachment to someone or something.

  • This does not say why your answer is right. It has no explanation. It has no original content. Please edit this answer to amend these deficiencies. – tchrist Jul 12 '19 at 21:06

When I read the title of your question 'Single word for “refusing to move to next activity unless present one is completed.”' I imdieately thought of 'go/no go'

From Wikipedia

In general go/no go testing refers to a pass/fail test (or check) principle using two boundary conditions or a binary classification. The test is passed only when the Go condition is met and also the No go condition fails.

But it does not meet several of your criteria, it is not a noun, it does not describe a person, and it is not a single word.

In my experience (US Army) it is often used like a single word to describe where the only options are move forward or not.

While it might not be exactly what you are looking for, it may provide alternate usage in the same context.


Depending on the context, you may be able to use prerequisite as a reference to the thought or process itself rather then the person. A prerequisite of future tasks may not be quite what you are looking for, but it is a different perspective to consider.


You could also describe someone as being fixated on a task. This seems to capture the sense you're looking for almost perfectly. But if you're describing a long-term personality trait rather than describing an immediate behavior, it might not work as well.

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