The Collaborative International Dictionary of English v.0.48:
Colorless \Col"or*less\, a.
1. Without color; not distinguished by any hue; transparent;
as, colorless water; a colorless gas.
Note: [Narrower terms: ashen, bloodless, livid, lurid, pale,
pallid, pasty, wan, waxen; neutral; white] [Also
See: achromatic, colorless.]
[1913 Webster + WordNet 1.5]
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.
[1913 Webster]
3. having lost its normal color.
Note: [Narrower terms: blanched, etiolate, etiolated,
whitened; bleached, faded, washed-out, washy;
dimmed, dulled, grayed; dirty; dull, sober,
somber, subfusc] colored
Syn: colorless, uncolored, uncoloured.
[WordNet 1.5 +PJC]