Raised bank loan, at first, the day before venture's termination (5)
I believe the answer is:
levee
'raised bank' is the definition.
(river bank)
'loan at first the day before venture's termination' is the wordplay.
'at first' says to take the initial letters.
'the day before' becomes 'eve' (eve is the night before something).
'termination' suggests the final letters.
The first letter of 'loan' is 'l'.
The final letter of 'venture' is 'e'.
'l'+'eve'+'e'='LEVEE'
(Other definitions for levee that I've seen before include "Embankment on the Mississippi" , "Artificial embankment" , "River bank reinforcement, particularly in the US" , "Riverside embankment" , "Gathering" .)