How do you spell Boisterous

Available Definitions:
1)  a. - Rough or rude; unbending; unyielding; strong; powerful.
2)  a. - Exhibiting tumultuous violence and fury; acting with noisy turbulence; violent; rough; stormy.
3)  a. - Noisy; rough; turbulent; as, boisterous mirth; boisterous behavior.
4)  a. - Vehement; excessive.