The word "onside" means being in a position where a player is allowed to participate in a certain activity or game according to the rules. Full definition
«We have some sort of onside kick for every game, based on how the team lines up,» says special teams coach Bobby Williams. (sbnation.com)
This is a great growth opportunity for lawyers who can harness technology and standardization, while staying onside with their law society obligations...» (rocketlawyer.com)
Ramsey looked surprised and the replays too showed that the midfielder was played onside by Martin Skrtel. (justarsenal.com)