Dictionary.com
Thesaurus.com

bash up

British  

verb

  1. slang (tr, adverb) to thrash; beat violently

"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

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

"I'm not going to bash up anybody - this is ridiculous, absolutely ridiculous."

From BBC