Adjective
illegally beyond a prescribed line or area or ahead of the ball or puck
Source: WordNetthe touchdown was nullified because the left tackle was offside Source: Internet
On the next play, St. Louis was penalized 5 yards for being offsides, moving the ball to the 40-yard line with 59 seconds left. Source: Internet
“You have had offsides by a fraction of a centimetre, literally by a nose. Source: Internet
However, Denver was called for an offsides penalty on the ensuing field goal attempt, giving Green Bay a new set of downs. Source: Internet
Cheaps were definitely offsides. Source: Internet