Riotous \Ri"ot*ous\, a. [OF. rioteux.] 1. Involving, or engaging in, riot; wanton; unrestrained; luxurious. The younger son . . . took his journey into a far country, and there wasted his substance with riotous living. --Luke xv. 13. 2. Partaking of the nature of an unlawful assembly or its acts; seditious. -- {Ri"ot*ous*ly}, adv. -- {Ri"ot*ous*ness}, n.