Bilk \Bilk\, v. t. [imp. & p. p. {Bilked}; p. pr. & vb. n. {Bilking}.] [Origin unknown. Cf. {Balk}.] To frustrate or disappoint; to deceive or defraud, by nonfulfillment of engagement; to leave in the lurch; to give the slip to; as, to bilk a creditor. --Thackeray.