мочить

To kill, to eliminate physically. Literally ”to wet”, derives from Russian cant in which a ”wet deal” way a business involving blood spilling.

Если, пардон, в туалете их [террористов] поймаем, и в сортире замочим.

(Путин В.В., 1999 г.)

If we, pardon me, find them [terrorist] in the toilets, we will polish them off in the john.

(V. Putin, 1999)

Врунов и жуликов мочить в сортире (“Polish off liars and swindlers in the john”),
Banner in Moscow (Dec. 2011)