Karate is one of Fallout GURPS skills. See: Fallout GURPS.
The skill of trained punching and kicking. When you punch or kick, use Karate skill rather than DX to determine the odds of hitting, and add !/5 of your skill level (round down) to damage. You may also parry attacks (even weapons) at @/3 skill. Your encumbrance must be Light or less to use Karate.”— Steve Jackson Games GURPS sources
With the abandonment of GURPS, Karate was merged into Unarmed.