Un*mer"ci*ful*ness

from The Collaborative International Dictionary of English v.0.48

Unmerciful \Un*mer"ci*ful\, a.
   Not merciful; indisposed to mercy or grace; cruel; inhuman;
   merciless; unkind. -- {Un*mer"ci*ful*ly}, adv. --
   {Un*mer"ci*ful*ness}, n.
   [1913 Webster]