Definitions for frag
A successful kill in a deathmatch game.
I'd been fighting him for ages, and then you stole my frag!
A fragmentation grenade
To deliberately kill (one's superior officer) with a fragmentation grenade.
To kill (another player) in a deathmatch computer game.
I fragged him but he fell off the ledge afterwards.
Origin: Shortened from fragmentation grenade.
The New Hacker's Dictionary
[from Vietnam-era U.S. military slang via the games Doom and Quake] 1. To kill another player's avatar in a multiuser game. “I hold the office Quake record with 40 frags.” 2. To completely ruin something. “Forget that power supply, the lightning strike fragged it.” See also gib.