noun
plural -loons
[count] a thin usually rubber bag that becomes larger when it is filled with air or gas
a picture or space in a cartoon that contains words that are spoken or thought by a character
go over like a lead balloon
US or Brit go down like a lead balloon
informal of a joke, suggestion, etc. :to fail completely
verb
-loons; -looned; -looning
[no obj] :to become bigger quickly
US