When it comes to antonyms for "chime in," there are several different options to choose from. Some possible antonyms may include "remain silent," "stay out of the conversation," "keep mum," "hold back," or "refrain from commenting." Essentially, any phrase that conveys the idea of not contributing to a discussion or participating in a group conversation could be considered an antonym for "chime in." While it's important to participate in group discussions and voice your opinions, sometimes it's equally important to listen and observe before jumping in with your own thoughts and ideas.