Shy — unsure (5)
I believe the answer is:
timid
I believe this is a double definition.
'shy' is the first definition.
(I know that shy can be written as timid)
'unsure' is the second definition.
(I know that unsure can be written as timid)
(Other definitions for timid that I've seen before include "Easily frightened" , "Mouse" , "Pusillanimous" , "Inclined to avoid people" , "Diffident, faint-hearted" .)