Tallow \Tal"low\, v. t. [imp. & p. p. {Tallowed}; p. pr. & vb. n. {Tallowing}.] 1. To grease or smear with tallow. 2. To cause to have a large quantity of tallow; to fatten; as, tallow sheep. Tallowing \Tal"low*ing\, n. The act, or art, of causing animals to produce tallow; also, the property in animals of producing tallow.