antithesis. From Wiktionary. Jump to: navigation, search. antithesis. Plural antitheses. An antithesis is an idea that is the opposite of another idea. noun, plural antitheses [an-tith-uh-seez] ) 1. opposition; contrast: the antithesis of right and wrong. 2. the direct opposite (usually followed by of or to): Her. The majority of plural nouns are formed by adding -s or -es (after an CH, S, SH, X or Z, and possibly O). Some will double the ending consonant (quizzes). antitheses. Definition from Wiktionary, the free dictionary. Jump to: navigation, search. English Noun. antitheses. plural of antithesis; Retrieved. Definition of antithesis written for English Language Learners from the Merriam-Webster Learner's Dictionary with audio pronunciations, usage examples, and count. Define antithesis: the exact opposite of something or someone—antithesis in a. Full Definition of antithesis. plural an·tith·e·sesplay play \-ˌsēz\ 1 a. What's the plural form of antithesis? Here's the word you're looking for. Definition of antithesis in English. noun (plural antitheses. the antithesis between the two approaches can be seen very clearly from a comparison of three. antithesis. Definition from Wiktionary, the free dictionary. antithesis (plural antitheses) A proposition that is the diametric opposite of some. The word antithesis means something that is the complete opposite of something else. A good sentence would be, acts of kindness are the antithesis of selfishness.