Found 2 items, similar to onside.
English → English (WordNet)
Definition: onside
onside
adj : not offside; being within the prescribed area of play [ant:
offside]
English → English (gcide)
Definition: onside
onside
\onside\ adj. (Sports)
Not offside; being within the prescribed area of play.
offside
[WordNet 1.5]