Hard __ to break (5)

I believe the answer is:
habit
(Other definitions for habit that I've seen before include "bent" , "Propensity" , "Settled tendency" , "can cause addiction" , "Ingrained behaviour" .)
I believe the answer is:
habit
(Other definitions for habit that I've seen before include "bent" , "Propensity" , "Settled tendency" , "can cause addiction" , "Ingrained behaviour" .)