Head cover from the rain (7)
I believe the answer is:
hairnet
'head cover' is the definition.
(I know that hairnet is a type of head cover)
'from the rain' is the wordplay.
'from' is an anagram indicator (from the letters).
'the'+'rain'='therain'
'therain' with letters rearranged gives 'HAIRNET'.
(Other definitions for hairnet that I've seen before include "Lock-keeper" , "It protects locks" , "A woman may wear this" , "Tonsorial restraint" , "It may keep locks" .)