OP(OverPowered) is used to complement a player or a weapon or a situation in the Game. For example, if you clutched on a team of 4 all by yourself (that’ll be awesome) then you will be called an OP player.

Or if a weapon is too damn good that can get you kills easily then that weapon is OP.

This term really got popular in India after many streamers and players like MortaL started using it.