Sentence:  Still more jealous bitterness was engendered by the O ' Banion gang 's seizure from a West Side marshalling yard of a freight-car load of Canadian whisky worth $ 100000 and by one of the biggest <WSD>coups</WSD> of the Prohibition era - the Sibley warehouse robbery , which became famous for the cool brazenness of the operation . 
Meaning of the word marked with <WSD> tags:  a brilliant and notable success