Feathery serpent? (3)
I believe the answer is:
boa
'serpent?' is the definition.
(boa constrictor, type of snake)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for boa that I've seen before include "Large S American snake" , "Potential killer" , "Fluffy scarf of feathers" , "native American" , "Long, thin, feathery scarf" .)