Mechanic is possibly hunkier (6)
I believe the answer is:
fitter
I believe this clue is a double definition.
'mechanic' is the first definition.
(I've seen this before)
'possibly hunkier' is the second definition.
(hunky means physically fit)
'is' is the link.
(Other definitions for fitter that I've seen before include "Worker assembling machinery - more healthy" , "Tradesman being in better shape" , "better equipped" , "less likely to feel fatigue" , "Workman" .)