Restore young fellow’s hat (7)
I believe the answer is:
stetson
'hat' is the definition.
(Stetson is an example)
'restore young fellow's' is the wordplay.
'restore' becomes 'stet' (I've seen this before).
'young fellow' becomes 'son' (male child).
'stet'+'son'='STETSON'
(Other definitions for stetson that I've seen before include "Style of hat" , "No tests (anag.)" , "Large hat" , "Ten-gallon hat" , "Man's hat with wide brim and high crown" .)