aberration
abnormality
anomaly
apparition
boutade
brainchild
brainstorm
bubble
capriccio
caprice
chimera
conceit
crackpotism
crank
crankiness
crankism
craze
crazy idea
crotchet
crotchetiness
delirium
deviancy
deviation
differentness
disposition
divergence
dottiness
dream
eccentricity
eidolon
erraticism
erraticness
fad
fancy
fantasque
fantastic notion
fantasy
fiction
figment
flimflam
fool notion
freak
freakiness
freakish inspiration
freakishness
hallucination
harebrained idea
humor
idea
idiocrasy
whimsier
whimsiest
irresponsibility
irresponsibleness
thought
firehose
looker-on
mock-tudor
naivety
naïveté
neuroticism
scornfulness
soupçon
surrealism
towatch
whimsey