Avoir un nom à coucher dehors

Literally: To have a name to sleep outdoors with

Example: “Le nouveau prof a un nom à coucher dehors ; personne n'arrive à le prononcer.” — The new teacher has a name nobody can say; not one of us can pronounce it.

Origin: A hotel today does not care what you are called. An inn did. Innkeepers were suspicious by trade, and after dark a traveler seeking a bed had to give his surname first — and a name that did not sound reassuringly Christian was a good way to be turned away and sent to sleep in the stable. Once admitted, dress and the standing of the name decided whether you got a good room or a bad one. With inns far rarer than hotels are now, and no realistic prospect of reaching the next one, a man with a name like that had every reason to travel with something warm to sleep in. The longer variant un nom à coucher dehors avec un billet de logement refers to the wartime billeting order that obliged a householder to lodge the soldier carrying it, but it looks bolted on to an expression that already existed.