Antonyms for the phrase "chiming in" would be words or phrases that indicate silence or not joining a conversation. These could include being quiet, refraining from commenting, abstaining from participating, or keeping mum. Other antonyms for chiming in could be phrases that negates a willingness to express an opinion or take part in a conversation, such as holding back, staying out of it, staying silent, or refusing to contribute. When you don't want to contribute or express yourself in a discussion, there are various ways to express this, and using these antonyms for chiming would help communicate this effectively.