cock-and-bull storynoun [ C ]
uk/ˌkɒk.ən.bʊl ˈstɔː.ri/us/ˌkɑːk.ən.bʊl ˈstɔːr.i/informal disapprovinga story that is obviously not true, especially one given as an excuse:
He gave me some cock-and-bull story about having to be at his cousin's engagement party.