Fandango accompaniment (6)
I believe the answer is:
'fandango accompaniment' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for guitar that I've seen before include "It's plucked or strummed" , "Six- or 12-stringed instrument" , "Air tug (anag)" , "Spanish instrument" , "Popular stringed instrument used by Beatles" .)