Hiaf 

High as fuck.

May be pronounced "Hee-yaff" for purposes of concealment when among unfavorable parties.

Bro I was hiaf last night after hittin' Derek's bong.

Hiaf by JeromesNiece July 24, 2013

HIAF 

Stands for "Huge In All Formats". This acronym is used when a professional athlete makes a big play that would help owners of that player in fantasy leagues. The opposite of HIAF is DIAF which stands for Droppable in All Formats.

Announcer: Albert Pujols had 3 home runs, 5 hits, and 4 runs!
Fantasy Analyst: HIAF!

Lebron James: Just look at my stats bro.
Fan: HIAF! Keeper status!

HIAF by *xpac taunt* October 28, 2011

Hiafj 

An abbreviation for He. Is. A. Flirty. Jerk.

Beatrice: DID I TELL YOU WHAT THOMAS HOW THOMAS TREATS ME?! <3
Nicole: NO! WHAT?!
Beatrice: He is so sweet! & He treats me so sweet!
Nicole: He is like that to me too! OH MY GOSH HIAFJ.
Beatrice: OH WOW! UGH. I thought I was special!

Hiafj by YouKnowWhoWroteThisSORRYNOW?! July 21, 2011

HIAFI 

He Is A Fucking Idiot

The president just finished speaking. HIAFI

HIAFI by gonzoAF March 13, 2020