boil over

• Audio (General Australian):

  (file)

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, of anger, etc.) To reach the point where aggressive action is taken.
   • 1913, Joseph C[rosby] Lincoln, chapter XIII, in Mr. Pratt’s Patients, New York, N.Y., London: D[aniel] Appleton and Company, →OCLC:

     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.

   • 2013 September 1, Phil McNulty, Liverpool 1-0 Man Utd, via BBC Sport:

     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 Gerrard.

3. (intransitive) To act aggressively angry.

   He boiled over all night.

4. (intransitive, of horse(s)) To buck aggressively.

   The stallion boiled over, throwing Robert from her back.

• overboil