noun

a person who supports or believes in the principles of communism.

I was very left-wing but I was never a communist

socialist,leftist,collectivist,radical socialist,anti-capitalist,Soviet,Bolshevik,Bolshevist,Marxist,neo-Marxist,Leninist,Marxist–Leninist,Trotskyist,Trotskyite,Maoist,commie,Bolshie,red,lefty