'offside' definitions:
Definition of 'offside'
(from WordNet)
adverb
Illegally in advance of the ball or puck
adjective
Illegally beyond a prescribed line or area or ahead of the ball or puck; "the touchdown was nullified because the left tackle was offside" [syn: offside, offsides] [ant: onside]
noun
(sport) the mistake of occupying an illegal position on the playing field (in football, soccer, ice hockey, field hockey, etc.)