Noun

(en noun)

(archaic) A boy; especially, a boy servant.

(archaic) Any male servant; a menial.

A tricky, deceitful fellow; a dishonest person; a rogue; a villain.

*

*:I had never defrauded a man of a farthing, nor called him knave behind his back. But now the last rag that covered my nakedness had been torn from me. I was branded a blackleg, card-sharper, and murderer.

*1977 , (Geoffrey Chaucer), (The Canterbury Tales) , Penguin Classics, p. 204:

*:God's bones! Whenever I go to beat those knaves / my tapsters, out she [my wife] comes with clubs and staves, / "Go on!" she screams — and its a caterwaul — / "You kill those dogs! Break back and bones and all!"

(cards) A playing card marked with the figure of a servant or soldier; a jack.

Noun

(en noun)

(zoology) A medium-sized rodent belonging to the genus Rattus .

* {{quote-magazine, year=2013, month=May-June, author= Charles T. Ambrose

, title= Alzheimer’s Disease , volume=101, issue=3, page=200, magazine=(American Scientist) , passage=Similar studies of rats have employed four different intracranial resorbable, slow sustained release systems—surgical foam, a thermal gel depot, a microcapsule or biodegradable polymer beads.}}

(informal) A term indiscriminately applied to numerous members of several rodent families (e.g. voles and mice) having bodies longer than about 12 cm, or 5 inches.

(informal) A person who is known for betrayal; a scoundrel; a quisling.

* 1883 , (Robert Louis Stevenson), (Treasure Island)

He’s more a man than any pair of rats of you in this here house.

(informal) An informant or snitch.

(slang) A person who routinely spends time at a particular location.

Scab.

Vagina.

A wad of shed hair used as part of a hairstyle.