Half of duo's styles are somewhat shabby (5)
I believe the answer is:
dusty
'somewhat shabby' is the definition.
(dusty can mean shabby or dirty)
'half of duo's styles' is the wordplay.
'half of' means to take half the letters.
'styles' becomes 'sty' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'duos' cut in half is 'du'.
'du'+'sty'='DUSTY'
'are' acts as a link.
(Other definitions for dusty that I've seen before include "Miller - or answer, may be!" , "Grubby" , "In need of a spring clean" , "Needing cleaning" , "Mr Miller" .)