Deadly force
A warning about deadly force
Deadly force was sufficient power applied to cause the death of someone.
In 2255 of the alternate reality, a sign outside Riverside Shipyard warned would-be trespassers that "use of deadly force has been authorized". (Star Trek)
In 2258 of the alternate reality, Alexander Marcus's rules of engagement for anyone who came upon "John Harrison to use deadly force on sight, should they fear for their lives or those of others. (Star Trek Into Darkness)
In 2366, when Kivas Fajo asked if Data had ever killed anyone, the android replied that he had not yet done so, though he had been programmed with the ability to use deadly force to defend someone. Aghast, Fajo asked how he could rationalize murder so easily, leading Data to clarify that he would never murder. (TNG: "The Most Toys")
In 2370, Captain Benjamin Sisko ordered Julian Bashir and his team to Deep Space 9's cargo bay 6 and to only deadly force if it was necessary. Later, Li Nalas asked General Krim not to resist, as he and his associates didn't want to use deadly force. (DS9: "The Siege")
In 2375, the Klingons, wishing to extradite Laas for killing one of theirs, argued that the Changeling was not justified in using deadly force, as he knew the knife would not hurt him. (DS9: "Chimera")