Meaning

noun a condition of damage or decay

noun a misconception that is fallacious and not true or valid

noun not mentally or physically healthy

originEtymology tree English unsound Proto-Germanic *-inōną Proto-Indo-European *-dyé- Proto-Germanic *-atjaną Proto-Indo-European *-tus Proto-Germanic *-þuz Proto-Germanic *-assuz Proto-Germanic *-inassuz Proto-West Germanic *-nassī Old English -nes Middle English -nesse English -ness English unsoundness From unsound + -ness.

Etymology from Wiktionary, CC BY-SA 3.0