Long flowing hair (4)
I believe the answer is:
mane
'long flowing hair' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for mane that I've seen before include "Neck hair of an animal" , "Animal's neck hair" , "Long thick hair" , "Lion or horse's 10 Across" , "(Lion's) hair on neck" .)