round on

round on verb

1. (intr, preposition) to attack or reply to (someone) with sudden irritation or anger

Collins English Dictionary – Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012 Idioms and Phrases with round on round on

Turn on, assail, especially verbally. For example, They all rounded on Jake for not upholding the party line. [Mid-1800s]

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.