Mock German physicist after beginning absorbing essay, say (6)

I believe the answer is:

ersatz

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'mock' is the definition.
(I've seen this before)

I cannot understand how the rest of the clue works.

(Other definitions for ersatz that I've seen before include "False" , "Cheap substitute or imitation" , "Imitation (from Ger.)" , "Substitute - fake" , "inferior type" .)

I've seen this clue in the Sydney Morning Herald.

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