offside \ˈ ̷ ̷| ̷ ̷\noun Etymology:off (III) + side 1. a.chiefly Britain: the right side (as of a horse or a vehicle) b.: the far or inferior side < into the rough surroundings of Chicago's offside — Science > 2.[off side]: an instance of being off side in a game < five-yard penalty for offside >