Entry 4 senses Webster, 1913 Boisterous /bois'-tẽr-əs/ · Bois·ter·ous · IPA /ˈbɔɪstəɹəs/ 01 a. Rough or rude; unbending; unyielding; strong; powerful. 1. Rough or rude; unbending; unyielding; strong; powerful.[Obs.] 2. Exhibiting tumultuous violence and fury; acting with noisy turbulence; violent; rough; stormy. “The waters swell before a boisterous storm.” — Shak. “The brute and boisterous force of violent men.” — Milton. 3. Noisy; rough; turbulent; as, boisterous mirth; boisterous behavior. “I like not that loud, boisterous man.” — Addison. 4. Vehement; excessive.[R.] “The heat becomes too powerful and boisterous for them.” — Woodward. Syn. Loud; roaring; violent; stormy; turbulent; furious; tumultuous; noisy; impetuous; vehement.