The term "opp" is commonly used as slang, particularly in urban and youth culture. It generally refers to an opponent or rival, especially in the context of street culture or conflicts. It can denote someone from a rival group or someone who is considered an adversary in various competitive or social situations.
The word "opp" is believed to be a shortened form of "opposition" or "opponent." It has gained popularity in modern slang, especially within hip-hop culture and among younger generations, often used in contexts involving rivalries.