verb/kʁɔ.ke l(ə) maʁ.mo/
to wait around for a long time.
“[…]avant qu'elle n'eût franchi le couloir et la porte d'entrée, Auguste croquait le marmot depuis plus de trois quarts d'heure.” — […] by the time she walked down the hallway and through the front door, Augusta had been waiting around for over three quarters of an hour.
Literally, “to pound on the marmot (an old-fashioned ornamental door knocker)”. The implication is one is waiting a long time for somebody to come to the door.