soundness

Etymology

The word came into English via Middle English soundenes and soundnes, which developed from Old English *sundnes and *ġesundnes (found in onsundnes), in turn from Proto-West Germanic *sundnassī (“soundness, health”). It can be broken down as sound + -ness, and is cognate with West Frisian sûnens (“soundness, health”), Middle Low German suntnisse (“soundness, health”), Middle High German suntnisse (“soundness, health”) and German Gesundnis (“health”).