Protection for the finger or the limb possibly (7)
I believe the answer is:
thimble
'protection' is the definition.
(I know that thimble is a type of cap)
'the limb possibly' is the wordplay.
'possibly' indicates an anagram.
'the'+'limb'='thelimb'
'thelimb' is an anagram of 'THIMBLE'.
'for the finger or' acts as a link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for thimble that I've seen before include "Cap to protect the finger while sewing" , "Protection from a needle" , "Thumb thing" , "Sewing tool" , "Protection for part of arm" .)