The word "un-fitting" refers to something that is not appropriate or suitable for a particular purpose or situation. Its antonyms include words such as fitting, suitable, appropriate, and relevant. These words suggest that a particular thing or idea is well-matched to its intended use or context, and that it meets the requirements, expectations, or standards set out for it. Other antonyms for "un-fitting" may include words such as apt, correct, proper, and fittingly. Overall, the antonyms for "un-fitting" convey a sense of harmony, alignment, and compatibility between an object, idea, or person, and the environment or context in which they exist.