Fellow on run avoids the company of the pack

I believe the answer is:

lone wolf

I'm a little stuck... Click here to teach me more about this clue!

'avoids the company of the pack' is the definition.
I can't tell whether this definition defines the answer.

'fellow on run' is the wordplay.
'run' indicates an anagram.
'fellow'+'on'='fellowon'
'fellowon' with letters rearranged gives 'LONE-WOLF'.

Can you help me to learn more?

(Other definitions for lone wolf that I've seen before include "Solitary person" , "Hunter away from pack" , "recluse" , "Independent agent" , "Person who prefers solitude" .)

I've seen this clue in the Irish Times.

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