Stun

Stun was the non-lethal setting on a directed energy weapon, such as a phaser, usually resulting in unconsciousness to a humanoid lifeform.

According to Q, stunning some lifeforms could kill them. 

In 2266, a Klingon duplicate of James T. Kirk stunned Montgomery Scott with a phaser after he refused his order to take the USS Enterprise (NCC-1701) to maximum warp.