Freight left on time (7)
I believe the answer is:
portage
'freight' is the definition.
(I've seen this in another clue)
'left on time' is the wordplay.
'left' becomes 'port' (left side of a ship - opposite of starboard).
'on' says to put letters next to each other (in a down clue, letters appear on others).
'time' becomes 'age' (an age is a period of time).
'port'+'age'='PORTAGE'
(Other definitions for portage that I've seen before include "Carriage" , "Transport between waterways" , "Carrying boat overland" , "Cost of carrying or transporting" .)