Kept being uncommunicative (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)
'uncommunicative' is the second definition.
(thesaurus)
'being' acts as a link.
(Other definitions for reserved that I've seen before include "Slow to show emotions" , "Uncommunicative, not extrovert" , "without emotion" , "Reticent; put by" , "Kept back" .)