After swindle leave African river (5)
I believe the answer is:
congo
'african river' is the definition.
(I've seen this before)
'after swindle leave' is the wordplay.
'after' means one lot of letters go next to another.
'swindle' becomes 'con' (synonyms).
'leave' becomes 'go' (to go is to depart or leave).
'con'+'go' is 'CONGO'.
(Other definitions for congo that I've seen before include "African runner" , "Central African country" , "flower" , "Africa's second longest river" , "Central African region" .)