Poison in conspiracy an idea (7)

I believe the answer is:

cyanide

'poison' is the definition.
(cyanide is poisonous)

'in conspiracy an idea' is the wordplay.
'in' indicates a hidden word.
'CYANIDE' is hidden within 'conspiracy an idea'.

(Other definitions for cyanide that I've seen before include "killer" , "Extremely poisonous salt" , "Nice day (anag) - poison" , "Poisonous compound" , "Highly toxic substance" .)

I've seen this clue in The Times.

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