engouement
a passing fad = un engouement passager « I don't believe environmental concern is a passing fad. » a fad for sth = un engouement pour qch « the current fad for all things Bollywood » to begin a fad for sth = lancer la mode de qch « they began a fad for slogan T-shirts that proclaimed everything about their wearer from "Babe" to "Whore" »