Freight ship caught beforehand (5)
I believe the answer is:
cargo
'freight' is the definition.
(synonyms)
'ship caught beforehand' is the wordplay.
'ship' becomes 'Argo' (ship in Greek myth).
'caught' becomes 'c' (cricket abbreviation).
'beforehand' means one lot of letters go next to another.
'argo' put after 'c' is 'CARGO'.
(Other definitions for cargo that I've seen before include "Goods carried by ship, aircraft" , "Freight, load" , "Freight on board ship" , "Stuff on board" , "Goods carried by vessel or vehicle" .)