Constricting snakes (4)
I believe the answer is:
boas
'constricting snakes' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for boas that I've seen before include "Large snakes" , "21 [SNAKES]" , "Long fluffy scarves of feathers" , "Cold-blooded creatures" .)