Drop from reserve XI? (7)

I believe the answer is:

subside

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'drop' is the definition.
(thesaurus)

'reserve xi?' is the wordplay.
'reserve' becomes 'sub' (substitute).
'xi?' becomes 'side' (I am not sure about this - if you are sure you should believe this answer much more).
'sub'+'side'='SUBSIDE'

'from' acts as a link.

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(Other definitions for subside that I've seen before include "(Flood) go down" , "Collapse" , "Sink, settle" , "Go down in level" , "Become less intense" .)

I've seen this clue in The Independent and The Sun.

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