mid-15c., humain, humaigne, "human," from Old French humain, umain (adj.) "of or belonging to man" (12c.), from Latin humanus "of man, human," also "humane, philanthropic, kind, gentle, polite; learned, refined, civilized." This is in part from PIE *(dh)ghomon-, literally "earthling, earthly being," as opposed to the gods (from root *dhghem- "earth"), but there is no settled explanation of the sound changes involved. Compare Hebrew adam "man," from adamah "ground." Cognate with Old Lithuanian žmuo (accusative žmuni) "man, male person."
Human interest is from 1824. Human rights attested by 1680s; human being by 1690s. Human relations is from 1916; human resources attested by 1907, American English, apparently originally among social Christians and based on natural resources. Human comedy "sum of human activities" translates French comédie humaine (Balzac); see comedy.
word-forming element denoting action, quality, or state, attached to an adjective or past participle to form an abstract noun, from Old English -nes(s), from Proto-Germanic *in-assu- (cognates: Old Saxon -nissi, Middle Dutch -nisse, Dutch -nis, Old High German -nissa, German -nis, Gothic -inassus), from *-in-, originally belonging to the noun stem, + *-assu-, abstract noun suffix, probably from the same root as Latin -tudo (see -tude).