Etymology
Advertisement
cunning (adj.)

early 14c., conning, "learned, skillful, possessing knowledge," present participle of connen, cunnen "to know," from Old English cunnan (see can (v.1)), from PIE root *gno- "to know." Also compare cun (v.). Sense of "skillfully deceitful, characterized by crafty ingenuity" is probably by late 14c. Related: Cunningly.

Related entries & more 
Advertisement
cunning (n.)

c. 1300, conninge, "knowledge, understanding, information, learning," a sense now obsolete, verbal noun from connen, cunnen "to have ability or capacity," from Old English cunnan (see can v.1). By mid-14c. as "ability to understand, intelligence; wisdom, prudence;" sense of "cleverness, shrewdness, practical skill in a secret or crafty manner" is by late 14c. 

Related entries & more 
cun (v.)

"to learn to know, inquire into," from Old English cunnian "to learn to know," ultimately from the same ancient root as can (v.1) and compare con (v.3). Surviving into 17c. and perhaps later in dialects. Also compare cunning.

Related entries & more 
can (v.1)

Old English 1st & 3rd person singular present indicative of cunnan "to know," less commonly as an auxiliary, "to have power to, to be able," (also "to have carnal knowledge"), from Proto-Germanic *kunnjanan "to be mentally able, to have learned" (source also of Old Norse kenna "to become acquainted, try," Old Frisian kanna "to recognize, admit, know," German kennen "to know," Middle Dutch kennen "to know," Gothic kannjan "to make known"), from PIE root *gno- "to know."

It holds now only the third sense of "to know," that of "to know how to do something" (as opposed to "to know as a fact" and "to be acquainted with" something or someone). Also used in the sense of may, denoting mere permission. An Old English preterite-present verb, its original past participle, couth, survived only in negation (see uncouth), but compare could. The present participle has spun off with a deflected sense as cunning.

Related entries & more 
canny (adj.)

"knowing, wise," 1630s, from a Scottish and northern English formation from can (v.1) in its sense of "know how to," + -y (2). A doublet of cunning that flowered into distinct senses in Scottish English. In the glossary to Scott's "Heart of Mid-Lothian" (1818) uncanny is defined as "dangerous," while canny, as used in the tale, is defined as "skilful, prudent, lucky ; in a superstitious sense, good-conditioned, and safe to deal with ; trustworthy ; quiet." Cannily is "gently" and canny moment is "an opportune or happy time."

"Knowing," hence, from 18c., "careful, skillful, clever," also "frugal, thrifty," and, from early 19c. (perhaps via Scott's novels) "cautious, wary, shrewd." Often used superciliously of Scots by their southern neighbors (and their American cousins).

The Canny Scot is so well known as scarcely to require description. He carries caution, cunning, and selfishness to excess. Deceitful when a purpose is to be accomplished, he is not habitually deceitful. One thing he never loses sight of—his own interest. But of his own interest he is not the most enlightened judge. ["The Natural History of Scotsmen," in The Argosy, December 1865]

Related: Cannily; canniness.

Related entries & more 
Advertisement
uncanny (adj.)

1590s, in a now-obsolete meaning "mischievous, malicious;" also in 17c., "careless, incautious; unreliable, not to be trusted," from un- (1) "not" + canny (q.v.) in its old Scots and Northern English sense of "skillful, prudent, lucky" (it is a doublet of cunning).

Canny had also a sense of "superstitiously lucky; skilled in magic." In Wright's "English Dialect Dictionary" (1900) the first sense of uncanny as used in Scotland and the North is "awkward, unskilful; careless; imprudent; inconvenient." The second is "Unearthly, ghostly, dangerous from supernatural causes ; ominous, unlucky ; of a person : possessed of supernatural powers".

From 1773, uncanny appears in popular literature from the North (Robert Fergusson, Scott), with reference to persons and in a sense of "not quite safe to trust or deal with through association with the supernatural." By 1843 it had a general sense in English of "having a supernatural character, weird, mysterious, strange." (OED notes this as "Common from c 1850"; Borges considers it untranslatable but notes that German unheimlich answers to it.)

The Scottish writers also use it with the meanings "unpleasantly hard; dangerous, unsafe."

Related entries & more 
*gno- 

*gnō-, Proto-Indo-European root meaning "to know."

It forms all or part of: acknowledge; acquaint; agnostic; anagnorisis; astrognosy; can (v.1) "have power to, be able;" cognition; cognizance; con (n.2) "study;" connoisseur; could; couth; cunning; diagnosis; ennoble; gnome; (n.2) "short, pithy statement of general truth;" gnomic; gnomon; gnosis; gnostic; Gnostic; ignoble; ignorant; ignore; incognito; ken (n.1) "cognizance, intellectual view;" kenning; kith; know; knowledge; narrate; narration; nobility; noble; notice; notify; notion; notorious; physiognomy; prognosis; quaint; recognize; reconnaissance; reconnoiter; uncouth; Zend.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit jna- "know;" Avestan zainti- "knowledge," Old Persian xšnasatiy "he shall know;" Old Church Slavonic znati "recognizes," Russian znat "to know;" Latin gnoscere "get to know," nobilis "known, famous, noble;" Greek gignōskein "to know," gnōtos "known," gnōsis "knowledge, inquiry;" Old Irish gnath "known;" German kennen "to know," Gothic kannjan "to make known."

Related entries & more 
wily (adj.)
"subtle, cunning, crafty," early 14c., from wile (n.) + -ly (1). Related: Wiliness. In 16c. English had wily-pie "cunning fellow."
Related entries & more 
sleight (n.)
"cunning," early 14c. alteration of sleahthe (c. 1200), from Old Norse sloegð "cleverness, cunning, slyness," from sloegr (see sly). Meaning "skill, cleverness, dexterity" is from late 14c. Meaning "feat or trick requiring quickness and nimbleness of the hands" is from 1590s. Term sleight of hand is attested from c. 1400.
Related entries & more 
Pratt 

surname, apparently from Old English *prætt (adj.) "cunning, astute;" related to the late Old English noun prætt "a trick" (compare Middle English prat-wrench "a cunning trick;" see pretty (adj.)). As a type of pottery, named for Staffordshire pottery manufacturer Felix Pratt (1780-1859).

Related entries & more