Said after something meaning it's the 100% truth. This cannot be used sarcastically, or any other -ly, except truthfully. You don't fuck with this shit.
It's origins come from South Park season 4 episode 16 'The Wacky Molestation Adventure.'
Person A: Holy shit, I just won $1,000,000 on this scratch ticket.
Person B: Bullshit.
Person A: No foolies.
Person B: Holy shit, buy me a car.
Person A: No.
Short-hand for the word floccinaucinihilipilification, meaning the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language).
Precedes or follows either a gratuitously disrespectful or honest remark, originated in New York City. Used in similar fashion to "no offense" or "to be honest," interchangeably.
Ya mans is wild buns, respectfully. Respectfully he's washed.
After school, The Modells on Jamaica Ave was active. Respectfully.