Somebody who first says that he will do something, and later kind-of forgets, or assumes that people forgot. The Russian word for it is "необязательность". I guess I am looking for a translation. It can be either an adjective, or a noun meaning such quality or condition.

Sample sentences could be:

This person is very {fill-the-word}.

{fill-the-word} has always been his weakness.

  • Single word requests are required to supply a sample sentence in which the desired word will fit.
    – Nigel J
    Mar 2, 2018 at 22:11
  • "and later kind-of forgets, or assumes that people forgot" - These are two very different types of behaviour. Simply forgetting to do things doesn't make someone a bad person. Deliberately not doing things and hoping others will forget is not the same at all. Not quite getting around to doing something yet but still intending to do it is another thing again.
    – nnnnnn
    Oct 31, 2019 at 23:35

6 Answers 6


I would call that person a "big talker".

The term refers to somebody who is "all talk and no action".

That term refers to somebody who makes lots of commitments, but doesn't follow through.

Depending on your context, that person can also be described as simply "unreliable".

  • 1
    I was going to say unreliable, but was feeling a little lazy at the time, so I'm glad you mentioned it. hunterlabourhire.com.au/…
    – Bread
    Mar 3, 2018 at 3:00


  1. the act of continuing a plan, project, scheme, or the like to its completion. (Random House)

Here are some ways of using it:

So-and-so is not very good at follow-through.

Lack of follow-through is so-and-so's primary weakness.


I would call him a hypocrite person.

  • Did you mean 'hypocritical person' ?
    – Nigel J
    Mar 4, 2018 at 17:14
  • A good answer on EL&U will be supported by references. In this case a citation from a dictionary and some discussion as to why that is applicable. In this case you might find that hypocrisy is more about "the practice of professing standards, beliefs, etc, contrary to one's real character or actual behaviour, esp the pretence of virtue and piety" * rather than a failure to follow-through on a promise. *(Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014)
    – Jim
    Mar 4, 2018 at 20:15

snollygoster:A shrewd, unprincipled person,that only think of himself

  • 1
    More context about your answer, a link to a dictionary definition, and an example of how it would fit in the sample sentences provided would make this a much better answer. You might also want to take a look at How do I write a good answer?. Jul 23, 2018 at 19:07
  • Interesting word, but the definition you've given doesn't match what was asked for because it doesn't apply specifically to not keeping promises.
    – nnnnnn
    Nov 1, 2019 at 3:21

This depends very much on context.

If the person were making boasts or threats, then the term paper tiger would fill your first space well. I don't think there's a single word which would fill the second as comfortably.

I'm going to assume from the Russian word you provided, though, that you mean something like they assumed (or acted as though) it were unnecessary to follow through, in which case I can think of several pairs that might work for you:

  • very lazy and pure laziness [lack of motivation]
  • … [no very] rather effete and passivity [lack of … something¹]
  • inconsistent and inconsistency [flakiness, lack of commitment]

Finally, @Michael_B has already suggested unreliable for the first position; I'd suggest spelling out the second as A lack of reliability but that's a personal style choice, not a hard-and-fast “grammar rule”.

¹ There are a lot of somethings that would fit here: strength, forcefulness, decisiveness, …


untrustworthy vocabulary.com adj

not worthy of trust or belief

noun: untrustworthiness

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