The figurative meaning "acute or penetrating in intellect or perception" was in Old English; hence "keenly alive to one's own interests, quick to take advantage" (1690s). Of words or talk, "cutting, sarcastic," from early 13c. Meaning "distinct in contour" is from 1670s. The adverbial meaning "abruptly" is from 1836; that of "promptly" is first attested 1840. The musical meaning "half step above (a given tone)" is from 1570s. Meaning "stylish" is from 1944, hepster slang, from earlier general slang sense of "excellent" (1940). Phrase sharp as a tack first recorded 1912 (sharp as a needle has been around since Old English). Sharp-shinned attested from 1704 of persons, 1813 of hawks.
In reference to devices, the sense of "behaving as though guided by intelligence" (as in smart bomb) first attested 1972. Smarts "good sense, intelligence," is first recorded 1968 (Middle English had ingeny "intellectual capacity, cleverness" (early 15c.)). Smart cookie is from 1948.
1590s, "sharp and painful, poignant, piercing," originally figurative, of pain or grief, from Latin pungentem (nominative pungens), present participle of pungere "to prick, pierce, sting," figuratively, "to vex, grieve, trouble, afflict" (from suffixed form of PIE root *peuk- "to prick"). For sense development, compare piquant; sharp (adj.).
Meaning "having powerful odor or taste, sharply affecting the sense of smell" is recorded by 1660s; in reference to writing, etc., "sharply affecting the mind, curt and expressive" is by 1850. The literal sense of "sharp, pointed" (c. 1600) is very rare in English and mostly limited to botany.
Middle English and early Modern English also had a now-obsolete verb punge "to prick, pierce; to smart, cause to sting," from Latin pungere. Related: Pungently.
also *ker-, Proto-Indo-European root meaning "to cut."
It forms all or part of: bias; carnage; carnal; carnation; carnival; carnivorous; carrion; cenacle; charcuterie; charnel; corium; cortex; crone; cuirass; currier; curt; decorticate; excoriate; incarnadine; incarnate; incarnation; kirtle; scabbard; scar (n.2) "bare and broken rocky face of a cliff or mountain;" scaramouche; scarf (n.2) "connecting joint;" scarp; score; scrabble; scrap (n.1) "small piece;" scrape; screen; screw; scrimmage; scrofula; scrub (n.1) "low, stunted tree;" scurf; shard; share (n.1) "portion;" share (n.2) "iron blade of a plow;" sharp; shear; shears; sheer (adj.) "absolute, utter;" shirt; shore (n.) "land bordering a large body of water;" short; shrub; skerry; skirmish; skirt.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit krnati "hurts, wounds, kills," krntati "cuts;" Hittite karsh- "to cut off;" Greek keirein "to cut, shear;" Latin curtus "short;" Lithuanian skiriu, skirti "to separate;" Old English sceran, scieran "to cleave, hew, cut with a sharp instrument;" Old Irish scaraim "I separate;" Welsh ysgar "to separate," ysgyr "fragment."