What is High-postin'?
1.
To front and/or profile; act like you got game; pose like you know the word; to boast, show off.
Possibly derived from basketball terminology; to high post is to position one's self offensively at the top of key. This can be taken as an affront to the defensive player's defensive prowess.
Mos Def says, "...I'm from Brooklyn
certain shit you just don't do
like
high-postin' when you far from
or like
high postin' when you all alone..."
See