To go out of one's way to help or provide a service to a friend/colleague/acquaintance. Often in exchange for nothing. Another way of describing a favor or act of altruism.
For example:
'I going KFC, what you having for lunch?' 'Got no money, do you want to Hook a brother up?' 'Okay I will HBU and get a bucket.'
By Dannie
[Hook] A [brother] Up
A request of information/access to something (often illegal) from one homeboy to another.
Homeboy A - "Yo nigga, I got me a fly new hat stand"
