in reserve
idiomPart ofreserve
in reserve — idiom
1. kept ready and not used yet, so that it can be brought out later if a problem ap
1.idiom
Definition
kept ready and not used yet, so that it can be brought out later if a problem appears or if extra help is needed.
Example
Élise always keeps a clean shirt in reserve in her desk drawer for surprise meetings.
The general held two battalions in reserve behind the front line.