After a short time the marshal gets cash (5)
I believe the answer is:
money
'cash' is the definition.
(cash is a type of money)
'after a short time the marshal' is the wordplay.
'after' says to put letters next to each other.
'a short time' becomes 'mo' (as in 'just a mo').
'the marshal' becomes 'ney' (I've seen this in other clues).
'mo'+'ney' is 'MONEY'.
'gets' acts as a link.
(Other definitions for money that I've seen before include "Cash, notes" , "Coins, banknotes, etc" , "Medium of exchange" , "It's the root of all evil" , "Mazuma, ackers or dosh" .)