Blue feathers for swallow? (4)
I believe the answer is:
down
I believe this is a triple definition!
'blue' is the first definition.
(both can mean sad)
'feathers' is the second definition.
(down can mean bird feathers)
'for swallow?' is the third definition.
(I've seen this in another clue)
(Other definitions for down that I've seen before include "Feathers of eider duck" , "Feathers or hair" , "when in adversity" , "Dispirited" , "See 10" .)