Sounding like principal hair on the necks of horses and lions (4)
I believe the answer is:
mane
'hair on the necks of horses and lions' is the definition.
I can't judge whether this defines the answer.
'sounding like principal' is the wordplay.
'sounding like' indicates a 'sounds like' (homophone) clue.
'principal' becomes 'main' (both can mean major).
'main' is a homophone of 'MANE'.
Can you help me to learn more?
(Other definitions for mane that I've seen before include "Long shaggy hair" , "Lion or horse's 10 Across" , "Animal's neck hair" , "Name for hair on horse's neck" , "Neck hair of an animal" .)