Bolshevik

Concise Oxford English Dictionary © 2008 Oxford University Press:
Bolshevik /ˈbɒlʃɪvɪk/

▶noun historical

• 1 a member of the majority faction of the Russian Social Democratic Party, which seized power in the Revolution of 1917.

• 2 a person with politically subversive or radical views.

– derivatives
Bolshevism noun,
Bolshevist noun.

– origin Russ., from bol′she ‘greater’ (with ref. to the greater faction).