Opp Boy 

Defined as someone from a rival gang and/or an enemy or someone you despise. Usually someone not part of your Mandem.

"Nah man this is the opp boy's block"

Opp Boy by UK Meanings January 21, 2021

Opp boy 

Insult - A term used to describe someone who is a cross between a snake and a wasteman.

He's an Opp Boy

He is moving like an Opp
That is Opp Boy movements

Opp boy by GiveMeaYard June 11, 2018