'pro-syndicalist' is formed from the prefix 'pro-' (from Latin 'pro', meaning 'for' or 'in favor of') combined with 'syndicalist' (from 'syndicalism').

'syndicalist' derives from French 'syndicalisme'/'syndicaliste' (late 19th century), itself related to French 'syndicat' (trade union) and ultimately from Late Latin/Medieval Latin 'syndicus' and Greek 'syndikos' meaning 'caretaker of an affair'. The modern compound 'pro-syndicalist' developed by adding the English prefix 'pro-' to indicate support.

Originally, 'syndicalist' referred specifically to advocates of syndicalism (a movement for trade-union-based direct action and worker control). With the prefix 'pro-', 'pro-syndicalist' has the straightforward contemporary meaning 'in favor of or supportive of syndicalism'.