ad·ven·tur·ism (ād-věn'chə-rĭz'əm) n. Involvement in risky enterprises without regard to proper procedures and possible consequences, especially the reckless intervention by a nation in the affairs of another nation or region: "American strategic interests would . . . be even more jeopardized by Soviet adventurism in the Middle East"(Christopher T. Rand). ad·ven'tur·ist adj. & n., ad·ven'tur·is'tic adj.