A sudden idea is a thought or concept that comes to mind suddenly and unexpectedly. It can be an INSPIRATION, a whim, or the result of a brainstorming session. INSPIRATION is an 11-letter term that refers to a sudden creative or intuitive thought that can lead to a new idea or invention. A whim is a 4-letter term that describes an unpredictable or sudden change in opinion or behavior. Brainstorming is a 10-letter term that refers to a group activity in which ideas are generated spontaneously and without judgment. Together, these three terms describe the concept of a sudden idea.