Habit back for good, in a manner of speaking (9)
I believe the answer is:
addiction
'habit' is the definition.
(drug habit)
'back for good in a manner of speaking' is the wordplay.
'back for' says the letters should be written backwards (I've seen 'backing for' mean this).
'good in' becomes 'da' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'a manner of speaking' becomes 'diction' (a person's way of speaking).
'da' back-to-front is 'ad'.
'ad'+'diction'='ADDICTION'
Can you help me to learn more?
(Other definitions for addiction that I've seen before include "habit that's hard to break" , "I did act on (anag.)" , "hard to stop" , "Bug one's caught" , "The origin of dependence" .)