The word 'copacetic' means satisfactory or fine, and its antonyms would be words that signify the opposite. Some of the antonyms of copacetic are inadequate, deficient, unsatisfactory, substandard, malfunctioning, or inadequate. In other words, if something is not copacetic, then it is not right or perfect, and it may have some faults or problems. Antonyms for copacetic can be used to describe something that is not up to par, or that falls short of expectations. It is important to use the correct antonym for copacetic in order to convey your message accurately.