Worker is in regional garb (but not cap) (7)
I believe the answer is:
artisan
'worker' is the definition.
(someone skilled in a particular craft)
'is in regional garb but not cap' is the wordplay.
I cannot quite understand how this works, but
'is' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for artisan that I've seen before include "Smith" , "Mechanic" , "Tsarina (anag.)" , "Skilled craftsperson" , "Skilled worker by hand" .)