American guy crosses river and leaves (5)
I believe the answer is:
chard
'american guy' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'crosses river and leaves' is the wordplay.
'crosses river' becomes 'd' (I can't justify this - if you can you should give a lot more credence to this answer).
'and' means one lot of letters go next to another.
'leaves' becomes 'char' (I've seen this in other clues).
'd' after 'char' is 'CHARD'.
Can you help me to learn more?
(Other definitions for chard that I've seen before include "Variety of beet with edible white leaf stalks" , "vegetable crop" , "Green vegetable" , "Leaf stalks from a kind of beet" , "Kind of (Swiss?) beet with edible leaves" .)