Killbilly is a term for armed and dangerous people (often white) who dwell in rural, mountainous areas in the United States, primarily in Appalachia and the Ozarks. They are often suspected, wanted or convicted of a violent crime, usually involving firearms.
Sweet ass movie by Quentin Tarantino that features the killer Bride hackin' and slash'in her way to Bill. Most people that I know thought it was stupid, but it really deserves alot of credit.
Ability used by snipers, soldiers, ninjas, secret agents, hitmen, and ex-girlfriends to take out a given target in a single move, be it in a virtual or real context. Can be used synonymously with "deathblow", but has added elegance - a killskill is always executed deftly and with a fair amount of style.
The gunslinger's killskills sent shivers through Fall Dog's spine - he had taken out both rider and horse in a single shot.