-ness

a native English suffix attached to adjectives and participles, forming abstract nouns denoting quality and state (and often, by extension, something exemplifying a quality or state):

darkness; goodness; kindness; obligingness; preparedness.

Origin

Middle English, Old English -nes, -nis, cognate with German -nis, Gothic -(n)assus; suffix orig. *-assus; -n- by false division of words with adj. and past participle stems ending in -n-; compare Old English efnes (later efen-nys) evenness

British Dictionary definitions for -ness

-ness

suffix

indicating state, condition, or quality, or an instance of one of these: greatness, selfishness, meaninglessness, a kindness

Word Origin

Old English -nes, of Germanic origin; related to Gothic -nassus

Word Origin and History for -ness

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 West Germanic *in-assu- (cf. Old Saxon -nissi, Middle Dutch -nisse, Dutch -nis, Old High German -nissa, German -nis, Gothic -inassus), from *-in-, noun stem, + *-assu-, abstract noun suffix, probably from the same root as Latin -tudo (see -tude).