A fixed idea that seems fanciful, odd, or crazy.
Состояние навязчивой идеи, как правило странной или сумасбродной.
Robert Fulton had a bee in his bonnet about a steamboat.
Grandmother has some bee in her bonnet about going to the dance.
She's got a bee in her bonnet about moving to New York!
У неё навязчивая идея о переезде в Нью-Йорк!