A deep pang is something added (9)
I believe the answer is:
appendage
'something added' is the definition.
I can't judge whether this definition defines the answer.
'a deep pang' is the wordplay.
'a deep pang' can be anagrammed to 'APPENDAGE'.
But, I am not sure how the anagram is indicated.
'is' is the link.
Can you help me to learn more?
(Other definitions for appendage that I've seen before include "E.g. insect's leg, feeler" , "It hangs on" , "Attached item" , "Something attached to a larger thing" , "It's added or attached to a larger or more important part" .)