Spartacist
Concise Oxford English Dictionary © 2008 Oxford University Press:
Spartacist /ˈspɑːtəsɪst, -təkɪst/
▶noun a member of the Spartacus League, a German revolutionary socialist group founded in 1916.
– origin from Spartacus, the pseudonym of one of its founders (orig. the name of a rebellious Roman slave).
'Spartacist' also found in these Oxford entries:

