Meaning of “boil over” - Learner’s Dictionary

boil over

phrasal verb with boil uk us /bɔɪl/ verb [ I, T ]

If a liquid that is being heated boils over, it flows over the side of the pan.


If a difficult situation or bad emotion boils over, it cannot be controlled any more and people start to argue or fight:

Finally her anger boiled over and she started hitting him.

(Definition of “boil over” from the Cambridge Learner’s Dictionary © Cambridge University Press)