Source : Webster's Revised Unabridged Dictionary (1913)

Operose \Op"er*ose`\ a. [L. operosus, fr. opera pains, labor,
   opus, operis, work, labor.]
   Wrought with labor; requiring labor; hence, tedious;
   wearisome. ``Operose proceeding.'' --Burke. ``A very operose
   calculation.'' --De Quincey. -- {Op"er*ose`ly}, adv. --
   {Op"er*ose`ness}, n.

Source : WordNet®

operoseness
     n : the quality of requiring extended effort [syn: {laboriousness},
          {toilsomeness}]