steepness

from WordNet (r) 3.0 (2006)

steepness
    n 1: the property possessed by a slope that is very steep [syn:
         {abruptness}, {precipitousness}, {steepness}] [ant:
         {gentleness}, {gradualness}]

from The Collaborative International Dictionary of English v.0.48

Steepness \Steep"ness\, n.
   1. Quality or state of being steep; precipitous declivity;
      as, the steepnessof a hill or a roof.
      [1913 Webster]

   2. Height; loftiness. [Obs.] --Chapman.
      [1913 Webster]