'pro-syndicalism' originates from Latin and French, specifically the Latin word 'pro' and the French word 'syndicalisme', where 'pro' meant 'for' and 'syndicalisme' (from 'syndicat') meant 'trade union/union organization'.

'pro-syndicalism' changed from the French term 'syndicalisme' (from 'syndicat'), which in turn derives from Medieval Latin/Old French forms related to Latin/Greek 'syndicus'/'syndikos' meaning a representative or advocate, and eventually became the modern English compound 'pro-syndicalism' by adding Latin 'pro-' to the French root.

Initially, related words referred to a 'representative' or 'trade-union' concept, but over time the compound came to mean specifically 'being in favor of syndicalism' (support for syndicalist political positions).