Wiktionary
fridge magnet
n. 1 A decoration attached to a magnet, displayed on the outside of refrigerator doors. 2 (context British slang English) A stupid person.
Usage examples of "fridge magnet".
Thus Becca - who, when I worked in publishing, gave me a worsening series of book-shaped clothes-brushes, shoehorns and hair ornaments - this year gave me a clapperboard fridge magnet.
He ordered from the young waiter who was keeping as close to him as a fridge magnet.