It's a one word term that means how well something actually works??

Different from something that works well, it's like.. imagine shopping for bras:

Some people buy bras based on looks, but some people don't value looks over {blank}.

(Meaning how well it supports, and all that.)

I think it starts with a c but I could be wrong.

  • 1
    It starts with an 'f'. See below.
    – thomj1332
    Jul 19, 2017 at 1:14
  • 1
    No, it starts with a c. See below.
    – Andrew Leach
    Jul 19, 2017 at 10:32
  • 2
    In that particular situation, I'd say ...but some don't value looks over fit. Or even, comfort.
    – Mari-Lou A
    Jul 19, 2017 at 10:59
  • 1
    Can you please explain what you mean by "how well something actually works" in your first sentence being "Different from something that works well" in your second sentence?
    – Lawrence
    Jul 19, 2017 at 14:37
  • 1
    Initially, just reading the question, I thought 'practicality'. Jul 20, 2017 at 4:47

8 Answers 8




the kind of action or activity proper to a person, thing, or institution; the purpose for which something is designed or exists; role.


This edit is from AndyT's comment. It gives you another noun to use that more closely matches the requested usage of qualifying whether or not something is working as designed. And from the discussion in the comments, I now prefer functionality over function.



1 The quality of being suited to serve a purpose well; practicality. ‘I like the feel and functionality of this bakeware’

1.1 The purpose that something is designed or expected to fulfil.


This edit also stems from the comments and discussion. It provides different parts of speech to use in sentences that are structured for such.


verb (used without object)

  1. to perform a specified action or activity; work; operate: The computer isn't functioning now. He rarely functions before noon.
  2. to have or exercise a function; serve: In earlier English the present tense often functioned as a future. This orange crate can function as a chair.




  1. of or relating to a function or functions : functional difficulties in the administration.
  2. capable of operating or functioning : When will the ventilating system be functional again?
  3. having or serving a utilitarian purpose; capable of serving the purpose for which it was designed


Common usages of these words in everyday speech:

"This phone is ugly, but I love its functionality."

"How well does this computer function?" "It is old, so not well."

"Your brand new Ford breaks down all the time. I drive an '85 Dodge, but at least it's functional."

  • 8
    Form follows function is a design principle that places function first before aesthetics. en.wikipedia.org/wiki/Form_follows_function
    – thomj1332
    Jul 19, 2017 at 1:17
  • 5
    This is a good answer, lacking only a source and a link (if possible) to the source. The definition in Merriam-Webster is close to the definition you quoted, but not exactly the same. Please add your source. I'm upvoting because I am confident you will. :)
    – ab2
    Jul 19, 2017 at 2:20
  • 6
    Also "functionality" would work well in the OP's sentence.
    – AndyT
    Jul 19, 2017 at 8:48
  • @thomj1332 the opposite principle is also alliterative: style over substance. Jul 19, 2017 at 15:09
  • The issue with this is that function isn't actually an exact fit. Function is a description of what something does, how it does it, but not how well it does a particular task. In the case of the bras, one that is uncomfortable and falls apart the moment you move but has built in health checking, water cooling, gps location, self cleaning robots, and so on has significantly more function than one that just provides good support and comfort.
    – Kaithar
    Jul 19, 2017 at 15:54

Consider efficacy.

efficacy noun The ability to produce a desired or intended result. ‘there is little information on the efficacy of this treatment’ - ODO

Your example would then be:

  • Some people buy bras based on looks, but some people don't value looks over efficacy.
  • efficacy or quality
    – Xanne
    Jul 19, 2017 at 8:13
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    @Xanne Efficacy is related to how well it works; quality relates more to how good it is.
    – Lawrence
    Jul 19, 2017 at 8:37
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    Efficacy is a perfect word for this use and is usually used in the context of drug function when discussing how good a particular substance is at achieving a goal.
    – Kaithar
    Jul 19, 2017 at 15:39
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    @brichins There is a difference, though. Efficacy has to do with whether (or even how much) something is effective in accomplishing a particular job, while efficiency has to do with the cost (however defined) of doing it.
    – Lawrence
    Jul 19, 2017 at 16:39
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    @Lawrence, no I'm agreeing with you, and providing an example of why, upon reflection, quality isn't quite right.
    – Mathieu K.
    Jul 19, 2017 at 16:44

You can also use utility, usefulness or usability.


utility NOUN

1 The state of being useful, profitable, or beneficial.
‘he had a poor opinion of the utility of book learning’

usefulness NOUN

The quality or fact of being useful.
‘faults that affect the book's usefulness’

usability (also useability) NOUN

The degree to which something is able or fit to be used.
‘it was important to measure the usability of each product’

  • Anything original here?
    – tchrist
    Jul 19, 2017 at 17:08

One word which does start with a c meaning "how well something can do its job" is capability.

  1. The power or ability to do something.

    ‘he had an intuitive capability of bringing the best out in people’
    ‘the company's capability to increase productivity’

    1.1 (often capabilities) The extent of someone's or something's ability.


A similar word is capacity:

2.1 The ability or power to do something.


However, since the principal use of capacity is to do with volume, how much something can contain or hold, using it in the example sentence may not be felicitous.

  • 1
    I would argue that capability is more a yes/no state... something having the capability to do something doesn't make a statement about how well it does that thing. I have might have the capability to compete in a marathon but that doesn't say anything about whether I'd make it more than 10m before falling over.
    – Kaithar
    Jul 19, 2017 at 15:43
  • I think I would call ten metres "limited capability".
    – Andrew Leach
    Jul 19, 2017 at 15:44
  • heh, so would I, but then we're in to multiple words. Actually I'd go for "limited capacity" since it's a duration issue rather than an issue with the ability during the duration, but that's splitting hairs. "I'm capable of providing that role in a limited capacity" vs "I have limited capabilities in that role"
    – Kaithar
    Jul 19, 2017 at 15:59

How about effectiveness?

From Dictionary.com:

effective - adjective
1. adequate to accomplish a purpose; producing the intended or expected result:

'effective teaching methods; effective steps toward peace.'

Related forms: effectiveness, noun

From Oxford:

effectiveness - noun

The degree to which something is successful in producing a desired result; success.

'the effectiveness of the treatment'


How about mechanics?

  • the machinery or working parts of something. "he looks at the mechanics of a car before the bodywork"
    • the way in which something is done or operated. "the mechanics of cello playing"
  • I was wondering about the relevance of mentioning people who work with machines (mechanics), but the meaning you're using fits quite well with the sample sentence.
    – Lawrence
    Jul 19, 2017 at 16:02
  • Not so much... the mechanics of performing a specific activity (such as pressing keys) are disconnected from how well that activity is performed. It's better to think of mechanics in the sense that the rules of a game are the mechanics of how that game is played. I think it's also the same issue of quality vs quantity, mechanics is like function in relating to position within a quantity operations rather than quality and efficiency in achieving a goal.
    – Kaithar
    Jul 19, 2017 at 16:06
  • Might be mistaken to mean "the way the thing moves", which is probably a consideration for the item of clothing in the sample sentence–I wouldn't know–but which wouldn't encompass things like ease of use, quality of materials and workmanship, and care instructions.
    – Mathieu K.
    Jul 19, 2017 at 16:23



  1. a state of physical ease and freedom from pain or constraint. "there is room for four people to travel in comfort"
  2. the easing or alleviation of a person's feelings of grief or distress. "a few words of comfort" synonyms: consolation, solace, condolence, sympathy, fellow feeling, commiseration;

You are looking for Quality.

Specifically, Good quality


Of a high standard. "Use homemade ice cream, or buy a good-quality luxury brand"

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