The antonyms for the term "sit-in" could be numerous, depending on the context. In the political sense, the opposite of a sit-in could be a protest march or a demonstration where people move around instead of remaining seated. In a different context, if sit-in is used to describe an event where someone settles in a spot for an extended time, the opposite could be a quick visit, a short stay, or just passing through briefly. Sit-ins might be considered passive, so the opposite could be considered aggressive, such as a disruptive demonstration, a riot, or a boycott. Ultimately, the antonyms for sit-in would depend on the particular situation and how the term is being used.