noun Informal.
  1. something that provides one with invigorating warmth: Hot soup is a good warmer-upper after skiing.
  2. something that serves to warm up an audience or group of participants before a main event: Radio stations played martial music as a warmer-upper before the prime minister's speech.

Origin of warmer-upper

1940–45; warm up + -er1, applied pleonastically to both v. and particle
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018