Make false accusations in case, losing case essentially (7)

I believe the answer is:

asperse

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'make false accusations in case losing' is the definition.
I can't judge whether this definition defines the answer.

'case essentially' is the wordplay.
'case' becomes 'as' (I am not sure about this - if you are sure you should believe this answer much more).
'essentially' becomes 'per se' (I've seen this in another clue).
'as'+'perse'='ASPERSE'

Can you help me to learn more?

(Other definitions for asperse that I've seen before include "Slander or calumniate" , "Disparage" , "Slander, spread false rumours about - as peers may?" , "Malign" , "Defame" .)

I've seen this clue in The Times.

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