Hanging it up is an idiomatic expression which means to retire or abandon a particular profession or activity. The antonyms for 'hanging it up' would be to continue, persist, pursue, or persist with the task, job, or role. The term may also refer to the literal meaning of hanging something up, in which case antonyms could be taking down or removing. The choice of antonyms depends on the context in which the term is used. For example, in sports, the antonyms for 'hanging it up' would be to keep competing or staying in the game.