Is it possible to use something similar to the English suffix "-able" to show that the action described can be done by someone or something? If not, what phrases do you suggest to use in its place?

  • 10
    Are you aware that the English suffix -able is borrowed directly from the Latin -abilis, with the same meaning?
    – fdb
    Commented Mar 2, 2017 at 15:03
  • 2
    Related question on Linguistics SE: linguistics.stackexchange.com/questions/3235/…
    – TKR
    Commented Mar 2, 2017 at 23:08

3 Answers 3


As brianpck mentioned, the English suffix "-able" is borrowed from Latin. The rules for applying it in Latin are more transparent than the English alteration between "-able" and "-ible". EDIT: And are actually even easier, now that I think about it.

  • First, choose your stem.

    • If the verb has a fourth principal part (supine) ending in -tus, remove the -tus and use that stem: amō, amātus > amā-
    • If it has a fourth principal part not ending in -tus, add an -i and use that stem: rideō, rīsus > rīsi-
    • Otherwise (e.g. posse), use the present infinitive stem (poss-)
  • If this stem already ends in -bi, attach -lis: habi- > habilis, nūbi > nūbilis > nubile.

    • These would originally have been habibilis and nūbibilis; the -bibi- was reduced to -bi- by haplogy.
  • Otherwise, attach -bilis.

All of the resulting adjectives are regular two-termination thirds: -ilis, -ilis, -ile.

My previous, overly complicated, explanation:

  • If the present stem ends in a vowel (including v and j), add -bilis: mov- > mōbilis > mobile
    • This can cause diphthongs to contract (ov → ō), since they're followed by a consonant
    • Usually vowel-stem verbs are obvious, but some are trickier; the stem of fleō is fle- rather than fl- (and thus it becomes flēbilis)
  • If the verb is first-conjugation, attach -ābilis to the present stem: am- > amābilis, dūr- > dūrābilis > durable.
  • Otherwise, attach -ibilis...
    • If the fourth principal part ends with -tus, or there is no fourth part, use the present stem: crēd- > crēdibilis > credible, poss- > possibilis > possible
    • Otherwise, use the supine stem: rīd- > rīsibilis > risible, vid- > vīsibilis > visible

There are also a few exceptions to these rules: for instance, stō, stāre > stăbilis rather than *stābilis. But *stābilis would still be easily understood.

(The more complicated rules worked, but there's no reason to memorize them if you already know the supine stem. Using the supine also eliminates "irregularities" like stăbilis from stō, stătus and flēbilis from fleō, flētus.)

  • 4
    Good answer! Two comments: (1) Are there exceptions to your rule? Facilis = "doable"? (2) Is "haplogy" an intentional pun?
    – Joonas Ilmavirta
    Commented Mar 2, 2017 at 19:11
  • @JoonasIlmavirta I was going to ask about exceptions too: I can think of a few. For instance, by these rules, it would be utor -> usibilis.
    – brianpck
    Commented Mar 2, 2017 at 19:17
  • @brianpck Hmm... Does fertilis come from ferre this way or is it a different derivative altogether? I'm trying to figure out if one should use the present stem as suggested by utilis (not usi(bi)lis).
    – Joonas Ilmavirta
    Commented Mar 2, 2017 at 19:21
  • @JoonasIlmavirta (2) is intentional, though I can change it if it's actually confusing. (1) probably though I can't think of many (brianpck's ūtibilis is a good catch); I feel like present stem + -ilis has a slightly different meaning than supine stem + -ibilis though I'm not sure exactly how or why (need to search more).
    – Draconis
    Commented Mar 2, 2017 at 19:24
  • 2
    @Draconis I got a good chuckle out of "haplogy," too, so no need to change it in my opinion.
    – cmw
    Commented Mar 2, 2017 at 19:38

The English suffix "-able/-ible" comes directly from Latin -abilis/-ibilis.

A search for Latin words ending in -bilis returns 737 results, of which the first few are:

  • abominabilis
  • accensibilis
  • acceptabilis
  • accessibilis
  • accusabilis
  • adfabilis
  • adibilis
  • adjutabilis
  • admirabilis
  • Would you consider facilis from facere the same derivative, even though there is no B (not facibilis)?
    – Joonas Ilmavirta
    Commented Mar 2, 2017 at 16:13
  • 1
    I think you're right: Priscian has a discussion about it, also citing the examples docilis and utilis. Interestingly, utibilis is also attested: I'm not sure if this was just to avoid the perceived dissonance (if that's the word) of -ibili- or if there is some other rule at work.
    – brianpck
    Commented Mar 2, 2017 at 19:11
  • 1
    @JoonasIlmavirta, semantically the two are close or maybe even indistinguishable, but technically they're not the same suffix, since they are two different forms and are not allomorphs. Another such pair are flexilis / flexibilis.
    – TKR
    Commented Mar 2, 2017 at 23:03

This might have been better as a comment, but I think it worth an answer to link generally to other answers and comments.

The University of British Columbia publishes an excellent introduction to this general kind of thing for both Latin and Greek at https://pressbooks.bccampus.ca/greeklatinroots/front-matter/preface/, where the linked page has a table of further linked contents. Chapter 5 is on 'Turning Latin Nouns into Adjectives', within which para. 34 discusses adjective-forming suffixes in English, while 35 and onwards give examples of endings and their derivation (including -ilis, -arius and -osus.)

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.