Dirtbag is a slang term often used to describe someone who is unscrupulous, unpleasant, and reprehensible. While there is no single antonym for the word, there are several words that can be used to describe a person who is the opposite of a dirtbag. For example, 'gentleman', 'honorable', 'trustworthy', 'respectable', and 'upright' are all antonyms of dirtbag. These words indicate that such a person is honorable, trustworthy, respectable, and upright in their character, and they are the opposite of the typical dirtbag. Using these antonyms can help convey a more positive tone and attitude towards someone who possesses these qualities.