pro-union

The word is a modern English compound formed by directly combining the Latin prepositional prefix "pro-" with the noun "union." The prefix "pro-," derived from the Proto-Indo-European root per- (meaning "forward, through"), entered English via Latin, consistently carrying its core sense of being "for" or "in favor of" something. The noun "union" traces back to Latin unus (one), from the PIE root oi-no- (one, unique). The literal construction "for-union" transparently conveys the modern abstract meaning of advocating for the unity and collective action of workers within a labor union or for the political amalgamation of states. Its formation follows a straightforward, logical pattern common in English for creating descriptive political and social adjectives.

Structure: pro (in favor of) + union (association) pro: Latin origin, a prefix meaning "for, in favor of, forward." Functions as a combining form indicating support or advocacy. union: Latin origin (from unio, meaning "oneness, unity"), via Old French. Functions as the core noun, meaning an organized association, especially of workers, or a political entity formed by uniting parts.