Vaporous

Adjective

 * 1) Relating to vapour; misty, foggy, obscure, insubstantial.
 * 2) * 1594, William Shakespeare, The Rape of Lucrece
 * O hateful, vaporous, and foggy night!
 * 1) * 1605, Francis Bacon, The Advancement of Learning
 * So whosoever shall entertain high and vaporous imaginations, instead of a laborious and sober inquiry of truth, shall beget hopes and beliefs of strange and impossible shapes.

Adverbs for Vaporous
curiously; strangely; terribly; confusingly; alarmingly; insecurely; mysteriously; intensely; foggily; mistily; steamily; bewilderingly; unhealthfully; dankly; hotly; suffocatingly; mustily.

Thesaurus
adulterated, aerial, aerodynamic, aerostatic, aery, air-built, airy, attenuate, attenuated, chimeric, chimerical, cloud-born, cloud-built, cloud-woven, cloudy, cut, dilute, diluted, dreamlike, ethereal, fanciful, fatuitous, fatuous, fine, flimsy, foggy, fuming, fumy, gaseous, gasified, gasiform, gaslike, gassy, gossamery, illusory, imaginary, insubstantial, mephitic, miasmal, miasmatic, miasmic, misty, mushy, oxyacetylene, oxygenous, ozonic, phantasmal, phantomlike, pneumatic, rare, rarefied, reeking, reeky, shadowy, slight, smoking, smoky, spirituous, steaming, steamy, subtile, subtle, tenuous, thin, thinned, thinned-out, uncompact, uncompressed, unreal, unsubstantial, vague, vaporing, vaporish, vaporlike, vapory, watered, watered-down, windy, wispy

Etymology
vapour + -ous