(US, colloquial, often preceded by hey) Used to express surprise or dissatisfaction with an action or statement of another person, especially to that person.

(chiefly in the negative) To have any knowledge (about something); have a clue. / Used other than figuratively or idiomatically: see have, first, idea.

To not know anything about something.

Alternative spelling of overvalued idea

Used to express regret for a foolish impromptu or impulsive past action.

(neurology, psychology) A neurological or cognitive phenomenon in which activation of a particular concept triggers a sensory-like experience.

A figurative landscape of ideas.

plural of ideascape