vaguenotion
nounUK /veɪɡ ˈnəʊʃən/
US /veɪɡ ˈnoʊʃən/
A vague notion is a fuzzy idea in your head that you cannot explain well.
I have a vague notion that we met before, but I can't remember where.
OTHER MEANINGS
2. A slight or unclear understanding of something.
She had only a vague notion of how the machine worked.
3. A rough plan or intention that is not fully formed.
He had a vague notion to start a garden someday.
4. An uncertain belief that something might be true.
I had a vague notion that it would rain, so I brought an umbrella.