Etymology: Middle English, from Old English scearp; akin to Old High German scarf sharp and perhaps to Old English scrapian to scrape — more at scrape
Date: before 12th century
1. adapted to cutting or piercing: as
a. having a thin keen edge or fine point
b. briskly or bitingly cold ; nipping <a sharp wind> 2. a. keen in intellect ; quick-witted b. keen in perception ; acute <sharp sight> c. keen in attention ; vigilant <keep a sharp lookout> d. keen in attention to one's own interest sometimes to the point of being unethical <a sharp trader>; also corrupt, unethical <sharp business practices> 3. keen in spirit or action: as a. full of activity or energy ; brisk <sharp blows> b. capable of acting or reacting strongly; especially caustic 4. severe, harsh: as a. inclined to or marked by irritability or anger <a sharp temper> b. causing intense mental or physical distress <a sharp pain> c. cutting in language or import <a sharp rebuke> 5. affecting the senses or sense organs intensely: as a. (1) having a strong odor or flavor <sharp cheese> (2) acrid b. having a strong piercing sound c. having the effect of or involving a sudden brilliant display of light <a sharp flash> 6. a. terminating in a point or edge <sharp features> b. involving an abrupt or marked change especially in direction <a sharp turn> c. clear in outline or detail ; distinct <a sharp image> d. set forth with clarity and distinctness <sharp contrast> 7. a. of a tone raised a half step in pitch b. higher than the proper pitch c. major, augmented — used of an interval in music 8. stylish, dressy • sharply adverb • sharpness noun Synonyms: sharp, keen, acute mean having or showing alert competence and clear understanding. sharp implies quick perception, clever resourcefulness, or sometimes questionable trickiness <sharp enough to spot a confidence game>. keen suggests quickness, enthusiasm, and a penetrating mind <a keen observer of the political scene>. acute implies a power to penetrate and may suggest subtlety and sharpness of discrimination <an acute sense of style>. II. adverb Date: before 12th century 1. in a sharp manner 2. exactly <1:15 sharp> III. noun Date: 14th century one that is sharp: as a. a sharp edge or point b. (1) a musical note or tone one half step higher than a note or tone named (2) a character ♯ on a line or space of the musical staff indicating a pitch a half step higher than the degree would indicate without it c. a needle with a small eye for sewing by hand d. a real or self-proclaimed expert; also sharper IV. verb Date: 1662 transitive verb to raise (as a musical tone) in pitch; especially to raise in pitch by a half step intransitive verb to sing or play above the proper pitch
New Collegiate Dictionary. 2001.