Fluff  —n. 1 soft fur, feathers, or fabric particles etc. 2 slang mistake in a performance etc. —v. 1 (often foll. By up) shake into or become a soft mass. 2 colloq. Make a fluff; bungle.  bit of fluff slang offens. Attractive woman.  fluffy adj. (-ier, -iest). Fluffiness n. [probably dial. Alteration of flue fluff]