a light bulb goes off in (one's) head(redirected from a light bulb goes off in their head)
a light bulb goes off in (one's) head
One is suddenly struck with an ingenious or inspired idea, insight, or revelation. In this expression, the phrasal verb "go off" means "turn on" or "become active." We spent hours trying to come up with a solution, when suddenly a light bulb went off in my head. I kept feeding him subtle hints about the truth of the matter, waiting for a light bulb to go off in his head. Hey, a light bulb just went off in my head—what if we try rerouting the funds through your sister's company to avoid higher tax rates?
Farlex Dictionary of Idioms. © 2022 Farlex, Inc, all rights reserved.