Source : Webster's Revised Unabridged Dictionary (1913)

Colorless \Col"or*less\, a.
   1. Without color; not distinguished by any hue; transparent;
      as, colorless water.

   2. Free from any manifestation of partial or peculiar
      sentiment or feeling; not disclosing likes, dislikes,
      prejudice, etc.; as, colorless music; a colorless style;
      definitions should be colorless.

Source : WordNet®

colorless
     adj 1: lacking in variety and interest; "a colorless and
            unimaginative person"; "a colorless description of the
            parade" [syn: {colourless}] [ant: {colorful}]
     2: weak in color; not colorful [syn: {colourless}] [ant: {colorful}]