Raven or robin (4)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
bird
'raven or robin' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for bird that I've seen before include "Feathered animal" , "Feathered creature" , "Flying creature" , "Avian" , "A prison sentence (slang)" .)