Dampness is from English 'damp' + the abstract suffix -ness; 'damp' is from Middle Low German damp ('vapour, steam'), of Germanic origin. The immediate etymological form is Middle Low German damp. The suffix -ness marks an abstract noun of quality or state, so the English form is shaped by recognizable word formation as well as by its inherited or borrowed base. In present use as a noun, it means "the state of being slightly wet", keeping the historical formation close to the word's ordinary semantic work. Related words include damp, dampen, and dampish.