Brainstorm

Noun

 * 1) 🇺🇸 A sudden thought, particularly one that solves a long-standing problem.
 * I had been working on the problem for weeks, and then I had a brainstorm and saw that the solution was easy.
 * 1) brainstorming
 * 2)  An unexpected mental error.

Verb

 * 1) To investigate something, or solve a problem using brainstorming.
 * 2) To participate in a brainstorming session.

Thesaurus
absurd idea, afebrile delirium, automatic response, blind impulse, boutade, brain wave, brainchild, bright idea, bright thought, brilliant idea, capriccio, caprice, conceit, crank, craze, crazy idea, crotchet, deliriousness, delirium, drive, fad, fancy, fantastic notion, fantasy, flash, fleeting impulse, flimflam, fool notion, freak, freakish inspiration, good idea, gut response, harebrained idea, humor, impulse, incoherence, inspiration, instinct, involuntary impulse, kink, lingual delirium, maggot, megrim, natural impulse, notion, passing fancy, quick hunch, quirk, ranting, raving, reflex, sudden thought, toy, urge, vagary, wandering, whim, whim-wham, whimsy