Impeccant means faultless, flawless, or without sin. Some antonyms for this word would be, guilty, culpable, blameworthy or imperfect, flawed, guilty, or tainted. These words represent the opposite of the meaning of impeccant, implying moral imperfection or sin. Some additional antonyms for the word impeccant could include dishonest, corrupt, sinful, or depraved. Antonyms for impeccant are useful in helping to describe actions or individuals who are not up to the high standard of impeccancy. It is necessary to incorporate antonyms when we want to convey our intentions and ideas effectively.