boil over

Verb

boil over (third-person singular simple present boils over, present participle boiling over, simple past and past participle boiled over)

1. (intransitive) To boil to such an extent as to overflow its container.
   • I forgot about the rice and it boiled over.
2. (idiomatic, intransitive, usually) To reach the point where aggressive action is taken.
   • He b'iled right over, and the tongue-lashing he give that boss Right Liver beat anything I ever listened to. There was heap of Scriptur' language in it, and more brimstone than you'd find in a match factory.1913, Joseph C[rosby] Lincoln, chapter XIII, in Mr. Pratt’s Patients, New York, N.Y.; London: D[aniel] Appleton and Company, →OCLC
   • But as the half progressed, Liverpool's pressure and high-tempo passing game increased United's frustration and it threatened to boil over on the stroke of half-time when Van Persie, who had already been booked, was involved in angry verbal exchanges with several Liverpool players, particularly...2013 September 1, Phil McNulty, Liverpool 1-0 Man Utd, via BBC Sport
3. (intransitive) To act aggressively angry.
   • He boiled over all night.
4. (intransitive) To buck aggressively.
   • The stallion boiled over, throwing Robert from her back.