round on

Related to round on: round games

round on

To suddenly attack, berate, or show hostility toward someone, especially verbally. I know he seems friendly, but he'll round on you in an instant if you disagree with him. I was really taken aback when Sally rounded on me because of what I said. It was just a joke, after all!
See also: on, round
Farlex Dictionary of Idioms.

round on

Turn on, assail, especially verbally. For example, They all rounded on Jake for not upholding the party line. [Mid-1800s]
See also: on, round
The American Heritage® Dictionary of Idioms by Christine Ammer.

round on

v.
To assail someone suddenly; turn on someone: The entire group rounded on me when I questioned their motives.
See also: on, round
The American Heritage® Dictionary of Phrasal Verbs.
See also:
  • round upon (one)
  • inveigh
  • inveigh against
  • inveigh against (someone or something)
  • be all over
  • be all over (one)
  • be all over somebody
  • give (someone) (a bit of) curry
  • pick away at (one)
  • be soft on (someone)