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.
[ ME, OE -nes, -nis, c. G -nis, Goth -( n ) assus; suffix orig. * -assus; -n- by false division of words with adj. and ptp. stems ending in -n-; cf. OE efnes (later efen-nys ) EVENNESS ]