one-horse . one-horse {adj. phr.} Insignificant; modest; provincial. Arnold's business is a one-horse operation; he never had a single employee. Categories: add yours add yours business {adj. phr.} Source: A Dictionary of American Idioms by A. Makkai, M.T. Boatner, J.E. Gates © 2025 To section: O Subscribe to: American Idioms► Also consider the parent subscriptions (3)Idioms feedEnglish languageHome page and general feed Leave my opinion Leave my opinion