quickscope

Etymology
From.

Noun

 * 1)  A rapid kill with a sniper rifle after scoping in.
 * 2)  The act of quickly scoping in with a sniper rifle (to kill an opponent).

Verb

 * 1)  To shoot (a character) by means of a quickscope.
 * 2) * 2013, Kenton Sheely (quoting “Misterfoxy”), First Person: War Stories from Gamespace, page 20:
 * I told them all to spectate me in first person, as I quick-scoped the five enemies from the top of the building.
 * 1) * 2015, Alan F. Meades (quoting “Soap”), Understanding Counterplay in Video Games, Routledge, page 155:
 * I was a bit annoyed at first as my previous few games had boasted some pretty high K/D whilst quickscoping and now I was being bombarded by constant noob tubes [gun-mounted grenades] and RPGs.
 * I was a bit annoyed at first as my previous few games had boasted some pretty high K/D whilst quickscoping and now I was being bombarded by constant noob tubes [gun-mounted grenades] and RPGs.