Source : Webster's Revised Unabridged Dictionary (1913)

Roust \Roust\, n. [Cf. Icel. r["o]st an estuary.]
   A strong tide or current, especially in a narrow channel.
   [Written also {rost}, and {roost}.] --Jamieson.

Roust \Roust\ (roust), v. t.
   To rouse; to disturb; as, to roust one out. [Prov. Eng. &
   Local, U.S.]