Don't hire Welsh terrier fancier as a fighter (8)
I believe the answer is:
wrestler
'fighter' is the definition.
(I know that wrestler is a type of fighter)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for wrestler that I've seen before include "Sumo type" , "One struggling" , "Professional fighter" , "Athlete trying to pin opponent to the ground" , "Ring fighter" .)