Source : Webster's Revised Unabridged Dictionary (1913)

Softness \Soft"ness\, n. [AS. s?ftness, s?ftnyss.]
   The quality or state of being soft; -- opposed to {hardness},
   and used in the various specific senses of the adjective.

Source : WordNet®

softness
     n 1: the property of giving little resistance to pressure [ant: {hardness}]
     2: a sound property that is free from loudness or stridency
        [ant: {volume}]
     3: a disposition to be lenient in judging others; "softness is
        not something permitted of good leaders"