'pro-communism' originates from Latin and French roots: the prefix 'pro-' (from Latin 'pro') meaning 'for, in favor of', combined with 'communism' (from French 'communisme', ultimately from Latin 'communis' meaning 'common').

'communism' changed from French 'communisme' (19th century), itself from Latin 'communis' ('common'), and the modern English compound 'pro-communism' was formed by prefixing English 'pro-' to 'communism' to indicate support for the ideology.

Initially it meant 'for common/shared ownership' in the sense of 'for the common' (via 'communis'), and over time the compound 'pro-communism' has come to mean 'in favor of the political ideology of communism'.