Pretty much every adjective that ends in the suffix -able or -ible gives rise to a related noun:

  • corruptible becomes corruptibility
  • mutable becomes mutability
  • respectable becomes respectability
  • irritable becomes irritability
  • gullible becomes gullibility

There are only two exceptions, as far as I'm aware: we have horrible and terrible, but no horribility or terribility. Now why would that be?

These words seem to have another strange aspect to them. If something is irritable then it is not able to irritate but inclined to be irritated. If I am respectable then I'm not able to respect, but inclined to be respected. The -able ending does not generally denote ability.

But horrible doesn't mean inclined to be horrified; it really does mean able to horrify. And terrible doesn't mean inclined to be terrified; it means able to terrify. In other words, these two exceptions to the rule about cognate nouns also seem to be exceptions with respect to what type of property they describe.

Are these two oddities related somehow?

  • 8
    There's already horror and terror, so the need for newly nouned adjectives is low. Commented Oct 16, 2014 at 19:54
  • What do you mean by 'cognate'? CDO, for instance, has a definition that would only allow cross-language cognates. Commented Oct 16, 2014 at 22:32
  • 1
    'Horribleness' and 'terribleness' are given by AHDEL; they are from the same stable as the adjectives. Commented Oct 16, 2014 at 22:45
  • @EdwinAshworth Ah, maybe cognates have to be cross-language, yes. I've edited the question to get rid of the word. Thanks. Commented Oct 16, 2014 at 22:47
  • 2
    Many -able/-ible words have -ableness forms - miserableness, for example. I expect at least some people find favorableness, favorability both perfectly acceptable (and perhaps distinguishable). Commented Oct 17, 2014 at 0:05

3 Answers 3


I have to agree with Papa Poule that the question arises from a false analysis: horrible and terrible are not -able/-ible words in quite the sense you describe, and the corresponding noun derivation doesn't apply.

Off the top of my head, I'd say ostensible might be placed in this group, and there may well be others. Conceivably the distinction could come from being words adapted from existing Latin constructions (horribilis etc), rather than constructed later from English elements (so the verb in question is horreo rather than horrify, etc). Although that's just a guess, so almost certainly wrong...

  • Just a guess, maybe, but worthy of my upvote for making sense of and, more importantly, for clarifying and putting some substance behind my observation.
    – Papa Poule
    Commented Oct 24, 2014 at 14:18

First, that's some good research & discovery there.

The -xble suffixes are irrelevent to the Q. and distract.
The thing to bring out is the other contender to -ity: the -ness suffix and how it differs, and thus gives -ity a run for its money.

-ity is essentially qualitative: tells the nature of sth. -ness is quantitative, showing the extent (of even a quality).

Now in the OP's two example cases, -ity has little use, and as such seldom seen. It's not, however, ungrammatical. The use of this suffix as in the title here too, may be incorrect: horribleness is what's meant.


I notice in your analysis of 'horrible' and 'terrible' concerning what type of property they describe that you go/junp from 'horrible' to 'horrify' and from 'terrible' to 'terrify', whereas the other examples do not require (benefit from) such (subjective, perhaps) word modification.

Working backwards from horrify and terrify, we could get 'horrifiable/horrifiability' and 'terrifiable/terrifiabiliy', which, if English words, would not be exceptions to either of the rules that you discuss. I'm certainly not trying to start a movement to coin these words, but I think the oddities pointed out in your question might have something to do with the fact that not all definitions of 'horrible' and 'terrible' involve things that 'horrify' or 'terrify.'

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