Fining \Fin"ing\, n. 1. The act of imposing a fin?. 2. The process of fining or refining; clarification; also (Metal.), the conversion of cast iron into suitable for puddling, in a hearth or charcoal fire. 3. That which is used to refine; especially, a preparation of isinglass, gelatin, etc., for clarifying beer. {Fining pot}, a vessel in which metals are refined. --Prov. xvii. 3.