Revealing little and putting it back in the new cover (8)
I believe the answer is:
reticent
'revealing little and putting it' is the definition.
I can't judge whether this defines the answer.
'back in the new cover' is the wordplay.
'back in' becomes 'ti' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'the new' becomes 'recent' (I've seen this before).
'cover' indicates putting letters inside.
'ti' put into 'recent' is 'RETICENT'.
Can you help me to learn more?
(Other definitions for reticent that I've seen before include "Not wanting to talk" , "Uncommunicative" , "Quiet" , "Reserved - taciturn" , "'Self-effacing, restrained (8)'" .)