cliché: a backstabber

Meaning: to attack someone unfairly (definition). 

Example: As a co-worker reporting discreetly to the boss, she was a backstabber scuttling his career.

Origins: From 1920’s, one who acts behind someone’s back or “stabs your back.” (Source 1. Source 2.) 

Rewrites: 

• a blindside attacker
• an ear thumper
• a kidney puncher
• a heel scraper or crusher
• a ponytail dipper or grabber

Discussion: I struggled to find something closer to “back stabber” but didn’t come up with anything. Perhaps you will?