onside
adj.in a position where you are ready to play or support someone. In sports like rugby, it also means being in a legal position to receive a pass.
adj.positioned in a way that allows for legal participation or support. In rugby, specifically refers to a player being in a position to receive a pass without being offside.
“The team is finally onside and ready to win.”
“After the coach explained the new strategy, the players felt onside with the plan and started practicing immediately.”
“The quarterback waited for the wide receiver to be onside before releasing the ball, ensuring the play would not be called for a penalty by the referees.”
“Lamine Yamal stayed onside to collect another Olmo pass and put away Barça’s fifth.”
“But before we get to all that, Büchner has got to get the room onside.”
From on + side.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.