knave /neɪv/ BrE AmE noun [countable]
[ Language: Old English ; Origin: cnafa 'boy, male servant' ]
1 . British English the playing card with a value between the ten and queen SYN jack :
the knave of hearts
⇨ ↑ card 1 (7)
2 . old-fashioned a dishonest boy or man
—knavish adjective :
cunning, knavish tricks
—knavishly adverb