Hit the ball with it but be gentle, you say (6)
I believe the answer is:
putter
'it but be gentle you say' is the definition.
The definition suggests a singular noun which matches the answer.
'hit the ball with' is the wordplay.
'hit' becomes 'putt' (putting is a kind of hitting).
'the ball with' becomes 'er' (I am not sure about this - if you are sure you should believe this answer much more).
'putt'+'er'='PUTTER'
Can you help me to learn more?
(Other definitions for putter that I've seen before include "Golf club used on greens" , "Golf-club" , "Type of golf club" , "Club used on the green" , "Club to use on the green" .)