Colourless poet returning? (4)
I believe the answer is:
drab
'colourless' is the definition.
(I've seen this before)
'poet returning?' is the wordplay.
'poet' becomes 'bard' (bard is a kind of poet).
'returning?' is a reversal indicator.
'bard' reversed gives 'DRAB'.
(Other definitions for drab that I've seen before include "Dull and boring" , "Colourless like bard" , "Not cheering" , "Shabby; a slattern (arch.)" , "Dull light brown colour" .)