-ity

Etymology

It is inherited from Middle English -ite, also -itie,^[2][3][4][5] borrowed from Old French -ité, also -ete, and directly borrowed from Latin -itās, stem -itāt-,^[6][7][4][8] the usual form of -tās (source of -ty) with a vowel before it,^[8][9][6] that vowel being either the stem vowel of the base or a connecting one.^[7][4][6] Thus suāvitās (“sweetness”) is formed on suāvis and pūritās (“purity”) on pūrus; after an i the ending became -etās, as in pietās and varietās.^[8] Wiktionary carries the Latin suffix back to Proto-Indo-European *-teh₂ts and calls it cognate with -th.^[1]

Semantic evolution

The suffix was added to many Latin adjective endings, which gave English the compound endings -acity, -ality, -arity, -bility, -idity, -ivity and -osity.^[8] As well as a state or condition, a word in -ity can mean an instance of it, as with a profanity or a monstrosity, or a quantity that measures it.^[9] Etymonline quotes Fowler's distinction: a word in -ity usually means the quality, an instance of it or all the instances, while a word in -ism means the disposition or those who feel it.^[7]

Meanings

Suffix

1. Forming nouns from adjectives that name a state, condition or quality: rarity, hostility.^[10][4][2]
2. Forming nouns for a single instance of such a quality: an oddity.^[9]
3. Forming nouns for the degree of a quality, or a quantity measuring it: density.^[9][4]

Word family

• absurdity
• authority
• purity
• suavity
• piety

Related words

• -ability
• -ibility
• -ty
• -th
• -ness

References

1. ^ a b c Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
3. ^ The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
4. ^ a b c d e Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
5. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
6. ^ a b c Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
7. ^ a b c Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
8. ^ a b c d Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
9. ^ a b c d Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
10. ^ Collins English Dictionary (2023), Glasgow: HarperCollins