Concealment of deliveries in vessel (5-2)
I believe the answer is:
cover-up
'concealment' is the definition.
(cover-up is a kind of concealment)
'deliveries in vessel' is the wordplay.
'deliveries' becomes 'over' (I've seen this before).
'in' indicates putting letters inside.
'vessel' becomes 'cup' (I've seen this in other clues**).
'over' going into 'cup' is 'COVER-UP'.
'of' is the link.
(Other definitions for cover-up that I've seen before include "Concealment of facts, should be exposed" , "Attempt to prevent discovery of a crime" , "Attempt to hide truth" , "Withholding of information" , "Whitewash" .)