Puzzle party hosted by retired British/American (6)
I believe the answer is:
sudoku
'puzzle' is the definition.
(I know that sudoku is a type of puzzle)
'party hosted by retired britishamerican' is the wordplay.
I cannot really understand how this works, but
'party' could be 'do' (do can informally mean a party) and 'do' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for sudoku that I've seen before include "Numeric puzzle" , "Japanese number puzzle" , "Popular logic-based puzzle" , "Number placement puzzle with a 9 x 9 grid" , "Boxing contest" .)