Head of the pack barking at customers (11)
I believe the answer is:
scoutmaster
'head of the pack' is the definition.
The answer and definition can be both people as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'barking at customers' is the wordplay.
'barking' indicates anagramming the letters ('barking' can informally mean mad).
'at'+'customers'='atcustomers'
'atcustomers' is an anagram of 'SCOUTMASTER'.
Can you help me to learn more?
(Other definitions for scoutmaster that I've seen before include "Organiser of a 5 of boys" , "Youth worker" , "Leading role created by Baden-Powell" , "Male youth group leader" , "One leading boys' troop" .)