Jolly camp plaintiff? (5)

I believe the answer is:

party

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This might be a double definition.

'jolly camp' is the first definition.
'party' can be an answer for 'camp' (thesaurus). I am not sure about the 'jolly' bit.

'plaintiff?' is the second definition.
(plaintiff is a kind of party)

Can you help me to learn more?

(Other definitions for party that I've seen before include "Political organization" , "Political organisation" , "Festivity" , "Celebratory social gathering" , "Social function" .)

I've seen this clue in The Times.

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