The Collaborative International Dictionary of English v.0.48:
Vaporousness \Va"por*ous*ness\, n. The quality of being vaporous. [1913 Webster] Vapor pressureWordNet (r) 3.0 (2006):
vaporousness n 1: cloudiness resulting from haze or mist or vapor [syn: haziness, mistiness, steaminess, vaporousness, vapourousness]