Mrs Deutsch - interminably dull and entirely corrupt (10)
I believe the answer is:
fraudulent
'corrupt' is the definition.
(thesaurus)
'mrs deutsch interminably dull and entirely' is the wordplay.
I cannot quite see how this works, but
'mrs' could be 'frau' (I have seen 'German Mrs ' mean 'frau' so perhaps 'mrs' could also mean 'frau') and 'frau' is found within the answer.
'and' could be 'n' (common abbreviation for 'and') and 'n' is found 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 fraudulent that I've seen before include "dishonest" , "Intended to deceive" .)