Other forms: coups de foudre
A coup de foudre is a sudden, overwhelming feeling or event, used most commonly to describe falling in love at first sight.
This French idiom literally translates to a "bolt of lightning" or "thunderbolt," but you'll rarely hear it used in meteorology, at least in English. Instead, it's used figuratively to describe the shock and suddenness of immediately falling in love with someone — or with something, like a place or a vocation. It's unexpected, sudden, powerful, and shocking. While almost always used in a romantic context, the term is occasionally used to describe a shocking discovery or a catastrophic event that changes everything in an instant.