Kept being shy (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)
'shy' is the second definition.
(reserved can mean shy or timid)
'being' is the link.
(Other definitions for reserved that I've seen before include "Booked, being unemotional" , "cool" , "Spoken for" , "Uncommunicative, not extrovert" , "Aloof" .)