From Middle English -ite, from Old French -ite, -ete, -eteit (“-ity”), from Latin -itātem, from -itās, from Proto-Indo-European *-teh₂ts (suffix). Cognate with Gothic -𐌹𐌸𐌰 (-iþa, “-th”), Old High German -ida (“-th”), Old English -þo, -þu, -þ (“-th”). More at -th.
- Used to form an uncountable noun from an adjective; especially, to form the noun referring to the state, property, or quality of conforming to the adjective's description.
- absurd + -ity → absurdity (“the quality of being absurd or inconsistent with obvious truth, reason, or sound judgment”)
- anonym(ous) + -ity → anonymity (“the quality or state of being anonymous”)
- modern + -ity → modernity (“the quality of being modern or contemporary”)
- precar(ious) + -ity → precarity (“a condition of existence without predictability or security, affecting material or psychological welfare”)
- Used to form a countable noun from an adjective, referring to someone or something that conforms to the adjective's description.
- absurd + -ity → [an] absurdity (“that which is absurd; an absurd action; a logical contradiction”)
- anonym(ous) + -ity → [an] anonymity (“that which is anonymous”)
- insipid + -ity → [an] insipidity (“something that is insipid; an insipid utterance, sight, object, etc.”)
- oddity + -ity → [an] oddity (“an odd or strange thing or opinion; a strange person; an oddball”)
- Used to form other nouns, especially abstract nouns.
- Many nouns formed with -ity are uncountable; those that are countable form their plurals in -ities.
- The addition of -ity to an adjective results in a shift of stress to the antepenultimate syllable; that is, words in -ity are stressed on the last syllable before the -ity, even in cases where this syllable is part of another suffix (as in words in -ability and -icity). Further, this shift typically results in a change in vowel quality; compare, for example, real and reality, where the sound [æ] in the second word is not present in the first. These vowel quality changes are usually consistent with the spelling of both forms — note that the letter <a> in the second word is present in the first — but sometimes spelling changes are seen, as with the suffix -ous, which when it combines with -ity produces the suffix -osity.
- While a final -c is pronounced [k], before -ity it becomes [s]; compare, for example, elastic and elasticity.
- Final -e is dropped before adding this suffix.