Widow-maker Meaning

Example : 1597, William Shakespeare, King John, act 5, sc. 2:  O, it grieves my soul,  That I must draw this metal from my side  To be a widow-maker!1906, Rudyard Kipling, "Harp Song of the Dane Women":  What is a woman that you forsake her,  And the hearth-fire and the home-acre,  To go with the old grey Widow-maker?1973, Peter F. Drucker, Management: tasks, responsibilities, practices, published 1999, page 316:  Finally, jobs that are 'widow-makers' should be rethought and restructured. In the heyday of the great sailing ships, around 1850, just before the coming of steam, every shipping company had a widow-maker on its hands once in a while. ... One typical 'widow-maker' has been the job of international vice-president in the large American company.