Validate feeling angry over American payment? (10)
I believe the answer is:
crosscheck
'american payment?' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'validate feeling angry over' is the wordplay.
'validate feeling' becomes 'check' (I can't justify this - if you can you should believe this answer much more).
'angry' becomes 'cross' (cross can mean annoyed or angry).
'over' means one lot of letters go next to another (in a down clue, some letters go over others).
'check' put after 'cross' is 'CROSSCHECK'.
Can you help me to learn more?
(Other definitions for crosscheck that I've seen before include "Make doubly sure" , "Verify by referring to other sources" .)