The phrase "smooth operator" typically refers to a suave and charming individual who is able to navigate social situations with ease. Antonyms for this term could include awkward, clumsy, bumbling, or stumbling. Other antonyms might include blunt, straightforward, or unsophisticated, as these words describe individuals who lack the charm and finesse typically associated with a smooth operator. Someone who is inconsiderate or tactless could also be considered an antonym for a smooth operator, as they are more likely to offend or put others off with their social interactions. Ultimately, the antonyms for "smooth operator" are numerous, as they describe a range of behaviors and dispositions.