Booked for being shy? (8)
I believe the answer is:
reserved
This clue is a double definition.
'booked' is the first definition.
('reserve' can be a synonym of 'book')
'being shy?' is the second definition.
(reserved can mean shy or timid)
'for' is the link.
(Other definitions for reserved that I've seen before include "Slow to reveal emotion" , "Shy - set aside" , "Set aside, earmarked" , "without emotion" , "Set aside; reticent" .)