Lacking in colour (7)
I believe the answer is:
anaemic
'lacking in colour' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for anaemic that I've seen before include "strangely pale" , "Pale, lacking vitality" , "Pale, weak in colour" , "Lacking vigour as in a cinema" , "Lacking in colour/vitality" .)