Short for "Woo Woo Woo, You Know It!". The full phrase is the catchphrase of WWE superstar Zach Ryder. The initials are a rallying cry of his fans, similar to WWJD (What Would Jesus Do).
by TheBaldOneMpls October 29, 2009
Non-Broski: I see people write it "Zach Ryder", isn't it "Zack" with a K?
Broski: WOO WOO WOO- YOU KNOW IT, bro! WWWYKI
Broski: WOO WOO WOO- YOU KNOW IT, bro! WWWYKI
by Mr Funny December 6, 2013