Lab \Lab\, v. i. [Cf. OD. labben to babble.] To prate; to gossip; to babble; to blab. [Obs.] --Chaucer.
Source: Webster's Revised Unabridged Dictionary (1913)
Lab \Lab\, n. A telltale; a prater; a blabber. [Obs.] ``I am no lab.'' --Chaucer.