vaporous (adj) – consisting of, resembling, or producing vapor; insubstantial or vague; imaginative, fanciful, or high-flown
BREAKDOWN: VAP- (steam or mist) + -OR (state) + -OUS (full of)
This word is built on the root VAP-, which means steam or mist.
Common VAP- words include evaporation and vapor.
More esoteric VAP- words include devaporation and pervaporate.