swear 1 antonyms and opposites of swear. Verb — To make a solemn promise or formal declaration, often under oath. Synonyms for swear blaspheme curse curse like a pagan curse like a trooper curse like a sailor cuss eff and blind eff and jeff execrate imprecate swear like a cutter swear like a pagan swear like a trooper swear like a sailor turn the air blue vilify Antonyms for swear mind one's language ← Back to the full definition of swear