1. "For," commonly used in modern slang. Pronounced 'foh'
2. "Fuck Off," commonly used during instant messaging, text messaging, and e-mail. Derived from similar abbreviations such as "mofo," short for 'mother fucker.'
3. "Fool," commonly used in modern slang. Pronounced 'foo'
4. "Full On," phrase created by Nathan Fillion. Commonly used to further intensify an already-intense or exciting phrase, such as "Double Rainbow."
- fo shizzle my nizzle
- fo you stupid bitch
- you's a damn fo
- that is so full on double rainbow! (fo dr)