Source : Webster's Revised Unabridged Dictionary (1913)

-ness \-ness\ [AS. -ness, -nyss, -nys; akin to OS. -nissi,
   nussi, D. -nis, OHG. -nissa, -nass[=i], -nuss[=i], G. -nis,
   -niss, Goth. -inasus.]
   A suffix used to form abstract nouns expressive of quality or
   state; as, goodness, greatness.