前所未闻

Explanation: Never heard of. 　　Usage: Partial official; as predicate, attributive; mean never heard of 　　Source: Song careful "unreliable words yellow woman": "This is unheard of, that is knowledge poor waste must go around, surprisingly strange day, Yi He do not have." Thesaurus:  be never known before and never to occur again, unprecedented; have no precedent in history, never hear in past history, peerless Antonym Group:  continuously or incessantly, (as) thick as hail, Continuum continuous, Continuous Without a break, continue continuous