Webster’s Revised Unabridged Dictionary · 1913
Knave
Knave (nāv), n. [OE., boy, servant, knave, AS. cnafa boy, youth; cf. AS. cnapa boy, youth, D. knaap, G. knabe boy, knappe esquire, Icel. knapi, Sw. knape esquire, knäfvel knave.] 1. A boy; especially, a boy servant. [Obs.] Wyclif. Chaucer.
O murderous slumber, Lay'st thou thy leaden mace upon my boy That plays thee music ? Gentle knave, good night. Shak.
2. Any male servant; a menial. [Obs.] Chaucer.
He's but Fortune's knave, A minister of her will. Shak.
3. A tricky, deceitful fellow; a dishonest person; a rogue; a villain. "A pair of crafty knaves." Shak.
In defiance of demonstration, knaves will continue to proselyte fools. Ames.
☞ "How many serving lads must have been unfaithful and dishonest before knave -which meant at first no more than boy — acquired the meaning which it has now !" Trench.
4. A playing card marked with the figure of a servant or soldier; a jack.
Knave child, a male child. [Obs.] Chaucer.
Syn. — Villain; cheat; rascal; rogue; scoundrel; miscreant.