French one dead? So suffer (7)

I believe the answer is:

undergo

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'suffer' is the definition.
(undergoing is a kind of suffering)

'french one dead? so' is the wordplay.
'french one' becomes 'un' (I've seen this in other clues. I am not sure about the 'french' bit.).
'so' becomes 'ergo' (synonyms).
'un'+'d'+'ergo'='UNDERGO'

Can you help me to learn more?

(Other definitions for undergo that I've seen before include "Suffer, endure" , "Endure or be subjected to" , "having to travel by tube" , "Stand" , "Suffer reverse" .)

I've seen this clue in The Hindu.

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