Lack \Lack\, v. t. [imp. & p. p. {Lacked}; p. pr. & vb. n. {Lacking}.] 1. To blame; to find fault with. [Obs.] Love them and lakke them not. --Piers Plowman. 2. To be without or destitute of; to want; to need. If any of you lack wisdom, let him ask of God. --James i. 5.