noun plural
1. usually capitalized F&H : war, famine, pestilence, and death personified as the four major plagues of mankind
the Four Horsemen still darken the skies — Harrison Smith
— with reference to Apoc 6:2-7 (NCE)
2. : four threatening forces of any kind
the four horsemen … scarcities, subsidies, doles, and inflation — Raymond Moley