The Collaborative International Dictionary of English v.0.48:

Boistous \Bois"tous\, a.
   Rough or rude; coarse; strong; violent; boisterous; noisy.
   [Obs.] --Chaucer. -- Bois"tous*ly, adv. --
   Bois"tous*ness, n. [Obs.] --Chaucer.
   [1913 Webster]