Do they occur when one is put out about an unconcluded deal? (5)

I believe the answer is:

ideas

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'do they' is the definition.
The definition suggests a plural noun which matches the answer.

I cannot understand how the rest of the clue works.

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(Other definitions for ideas that I've seen before include "Thoughts, perceptions" , "Theories" , "Brain waves" , "Thoughts from Sadie" , "plans" .)

I've seen this clue in the Evening Standard.

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