Furtive and crafty (3)
I believe the answer is:
sly
'furtive and crafty' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for sly that I've seen before include "Sneaky" , "Wily, shifty" , "Doing things in unpleasant and secret way" , "Devious, cunning" , "Crafty, devious" .)