coup de foudre

 
Pronunciation: /ˌkuː də ˈfuːdr(ə), ku də fudʀ/

noun (plural coups de foudre pronunc. )

  • a sudden unforeseen event, in particular an instance of love at first sight: their fateful meeting caused a coup de foudre that grew into lifelong love

Origin:

French, literally 'stroke of lightning'