Reticence (7)
I believe the answer is:
reserve
'reticence' is the definition.
(I know that reticence can be written as reserve)
This is the entire clue.
(Other definitions for reserve that I've seen before include "keep for oneself" , "Twelfth man < 's coolness" , "Keep for someone - spare bod" , "One on bench" , "Modesty- store" .)