One moving between banks, somewhat penniless (4)
I believe the answer is:
nile
'one moving between banks' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'somewhat penniless' is the wordplay.
'somewhat' indicates a hidden word.
'NILE' can be found hidden inside 'penniless'.
Can you help me to learn more?
(Other definitions for nile that I've seen before include "River that's Blue and White" , "eastern flower" , "Line (anag)" , "Cleopatra's river" , "Current" .)