Clear deliveries ahead of time (5)
I believe the answer is:
overt
'clear' is the definition.
(thesaurus)
'deliveries ahead of time' is the wordplay.
'deliveries' becomes 'over' (I've seen this before).
'ahead of time' becomes 't' (I've seen this in other clues).
'over'+'t'='OVERT'
(Other definitions for overt that I've seen before include "Open to view" , "Done in an obvious way" , "not disguised" , "Open and obvious" , "Open and unconcealed" .)