- aberration
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- bee
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- capriccio
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- chimera
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- freak
- freakish inspiration
- hallucination
- harebrained idea
- humor
- idea
- idiosyncrasy
- idle fancy
- illusion
- image
- imagery
- imagination
- imaginativeness
- imagining
- impression
- inclination
- insubstantial image
- invention
- kink
- maggot
- make-believe
- megrim
- mind
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- oddity
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- peculiarity
- phantasm
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- quirk
- romance
- screw
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- thought
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- trip
- twist
- urge
- vagary
- vapor
- vision
- whim
- whimsy
- whim-wham
- wildest dreams