Raise embankment in sound (4)
I believe the answer is:
levy
'raise' is the definition.
(I know that raise can be written as levy)
'embankment in sound' is the wordplay.
'embankment' becomes 'levee' (I've seen this before).
'in sound' shows a homophone (sound like).
'levee' is a homophone of 'LEVY'.
(Other definitions for levy that I've seen before include "Tariff" , "Impose tax/fee/fine" , "Impose and collect (money)" , "Financial charge" , "Imposition of charge" .)