Up your sleeve - Idioms by The Free Dictionary
up your sleeve
up (one's) sleeve
Of a plan or advantage, kept in secret so it can be utilized if and when it is required. A reference to cheating at a card game by hiding a favorable card up one's sleeve. My stamina is the ace up my sleeve for this race—the other runners don't stand a chance! I've got a few tricks up my sleeve if he decides to pursue legal action against me.
up your sleeve (of a strategy, idea, or resource) kept secret and in reserve for use when needed.
References in periodicals archive
Clearly, Roy is one of our industry's most well respected managers who has the same no nonsense, roll up your sleeves
approach to work that is so much a vital part of our company's culture.