Harridan's dead crafty (6)
I believe the answer is:
shrewd
'crafty' is the definition.
(I've seen this before)
'harridan's dead' is the wordplay.
'harridan' becomes 'shrew' (I've seen this before).
'dead' becomes 'd'.
'shrew'+'d'='SHREWD'
(Other definitions for shrewd that I've seen before include "Canny and calculating" , "worldly wise" , "Canny and with sound judgement" , "Having good judgment" , "Astute or crafty" .)