Little time to be impatient without initially seeming unforthcoming (9)
I believe the answer is:
secretive
'unforthcoming' is the definition.
(to be unforthcoming is to act secretively)
'little time to be impatient without initially seeming' is the wordplay.
I cannot really see how this works, but
'time' could be 'ret' (I've seen this in other clues) and 'ret' is found in the answer.
This explanation may well be incorrect...
(Other definitions for secretive that I've seen before include "Tending to hide things" , "Very private" , "Unforthcoming" , "giving nothing away" , "Inclined to concealment" .)