Crossword Genius

What Mayerhof and Zamenhof do that’s final (3,2)

Ross

I believe the answer is:

end of

'that's final' is the definition.

'what mayerhof and zamenhof do' is the wordplay.
I cannot quite understand how this works, but
'and' could be 'n' (common abbreviation for 'and') and 'n' is located in the answer.
'do' is present in the answer.
The remaining letters 'ef' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...

(Another definition for end of that I've seen is " last word".)

I've seen this clue in The Times.
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