Short for "facts, bitch" usually in response to a painfully obvious statement.
"Wow, you are so good at life. Everyone should be you."
"Fax b."
by Aja Lee October 21, 2016
only to be used when a great proverb or truth has been spoken; widely used in the bronx among deadass NY niggas.
"yo, did you hear about what happened last night with bryce? nobody should cheat on his girl's best friend. that shit mad fucked up"

"fax, b. that shit ain't right"
by maxmoefoeofficial October 25, 2017