"sw" means sarcasm warning, derived from an internet
forum when attempting to "flame" a "noob". It is a
shorthanded way of expressing a sarcastic
statement that might otherwise come of as sincere. It is an internetism.

nsw,
ysapky,
fyp,
pp/mm,
jopke,
mronos,
mobney
...
...
...
...

SW (acronym) meaning: to smoke weed

Stands for Smith and wesson, maker of the S&W .500, the most powerful handgun on earth.

SW, or 'Secret Wookie'. A lady who has well disguised but excessive body hair. SWs can be identified by examining the arm hair and eyebrows.

an expression of happiness

A short way of saying "super weapon" to CNC players.