take a rain check

take a rain check (third-person singular simple present takes a rain check, present participle taking a rain check, simple past took a rain check, past participle taken a rain check)

1. (idiomatic) To request or accept a rain check (an agreement from a merchant to honor a special offer, temporarily unavailable, after the expiration date).
2. (idiomatic, figurative) In social interactions, to request a deferred invitation. To "take a rain check" is a polite way to turn down an engagement, usually with the implication that one is simply postponing it and another time might be acceptable.

   I can't go with you to the museum this Saturday, but can I take a rain check?

• take a raincheck