- apprehension
- assume
- assumption
- bee
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- capriccio
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- climate of opinion
- community sentiment
- conceit
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- crank
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- estimate
- estimation
- fad
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- flimflam
- fool notion
- freak
- freakish inspiration
- general belief
- harebrained idea
- humor
- idea
- illusory
- image
- imaginativeness
- imago
- impression
- inclination
- inspiration
- intellection
- intellectual object
- judgment
- kink
- lights
- maggot
- megrim
- memory-trace
- mental image
- mental impression
- mind
- natural impulse
- notion
- observation
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- passing fancy
- perception
- posture
- presumption
- quick hunch
- quirk
- reaction
- recept
- reckon
- reflection
- representation
- sentiment
- supposition
- surmise
- theory
- thought
- toy
- vagary
- vaunting
- view
- way of thinking
- whim
- whimsy
- whim-wham