Kept quiet (8)
I believe the answer is:
reserved
I believe this is a double definition.
'kept' is the first definition.
(to keep is to reserve or hold onto)
'quiet' is the second definition.
(thesaurus)
(Other definitions for reserved that I've seen before include "Uncommunicative, not extrovert" , "Slow to reveal emotions" , "Aloof" , "Quiet, not given to showing emotion" , "cool" .)