a way more awesome way of saying fo sho, a commonly used term for the phrase "for sure" which means definately, or that's cool or an affirmative response to something you are down with. Synonymous with mos def, shonuff, hell yeah, downskis, dow, 10-4, affirmative.
chanel: we are gonna chill later yeah?
\fa SHOW skee\
1. A way better, proper way to say for sure.
2. A term which is said during a flick of your middle finger and anothers middle finger usually signaling the confirmation of brotherhood and/or friendship.
1.Me: Yo Chammy should I bang that twat over there.
Chammy: Foshoski bro