Skilled worker is wearing plaid, though hatless (7)
I believe the answer is:
artisan
'skilled worker' is the definition.
(artisan is a kind of skilled worker)
'is wearing plaid though hatless' is the wordplay.
I cannot quite see how this works, but
'is' is present in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for artisan that I've seen before include "crafty person?" , "one in command of craft?" , "Skilled worker by hand" , "man with skill" , "Skilled worker at craft or trade" .)