The quality or state of being damp, wet, or having excessive moisture in the air.
From Middle English 'dank' (possibly from Old Norse 'dökkr' meaning dark) combined with the suffix '-ness' which forms nouns from adjectives. The meaning evolved from 'dark and gloomy' to specifically describe moist, humid conditions.
Dankness has a funny double life in modern slang—while it technically means dampness, younger speakers use it to mean something is awesome or excellent, completely flipping the original negative meaning into something positive!
Complete word intelligence in one call. Free tier — 50 lookups/day.