a public official appointed to investigate citizens' complaints against government agencies or officials that may be infringing on the rights of individuals
a person employed by an institution to investigate complaints against it
Origin:
Swed < ombud, a deputy, representative (< ON umboth < um, umbe, about < IE *mbhi-, var. of *ambhi-, around, on both sides (> ambi-) + ON bjotha, to offer, bid, akin to OE beodan: see bid + man, man