1A counter-revolutionary force which opposed left-wing insurgents who had seized power in Finland in 1918; a member of this force.
2A counter-revolutionary force which opposed the Bolsheviks during the Russian Civil War (1917–22); a member of this force.
3Generally. Any of several counter-revolutionary groups; a member of such a group.
Early 20th century; earliest use found in The Times. From white + guard, probably after Red Guard.