i Register
In some senses, notion is marked as obsolete, colloquial. Watch for register when choosing this word.
ADJ
absurd, peculiar, ridiculous | hazy, vague
faintest, foggiest
She didn't have the foggiest notion about what her son was studying at university.
romantic | accepted, conventional, traditional | preconceived
general
Many people share a general notion that breakfast is the most important meal of the day.
simple, simplistic
VERB + NOTION
have
She had a silly notion that cats could understand every word she said.
reject | accept | support
dispel
The teacher worked hard to dispel the notion that math is only for clever students.
PREP
~ of
She had a strange notion of what made a good friend.