Disingenuous (6)
I believe the answer is:
artful
'disingenuous' is the definition.
(synonyms)
This is all the clue.
(Other definitions for artful that I've seen before include "Cunningly clever like Dickens Dodger" , "Crafty or cunning" , "Dickens boy, an . . . . . . Dodger" , "Cunning, wily" , "Sly" .)