Merriam-Webster Collegiate Dictionary - sharp

 I. adjective  Etymology: Middle English, from Old English scearp; akin to Old High German scarf ~ 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 ~ wind  2.  a. keen in intellect ; quick-witted  b. keen in perception ; acute ~ sight  c. keen in attention ; vigilant keep a ~ lookout  d. keen in attention to one's own interest sometimes to the point of being unethical a ~ trader; also corrupt, unethical ~ business practices  3. keen in spirit or action: as  a. full of activity or energy ; brisk ~ blows  b. capable of acting or reacting strongly; especially caustic  4. severe, harsh: as  a. inclined to or marked by irritability or anger a ~ temper  b. causing intense mental or physical distress a ~ pain  c. cutting in language or import a ~ rebuke  5. affecting the senses or sense organs intensely: as  a.  (1) having a strong odor or flavor ~ cheese  (2) acrid  b. having a strong piercing sound  c. having the effect of or involving a sudden brilliant display of light a ~ flash  6.  a. terminating in a point or edge ~ features  b. involving an abrupt or marked change especially in direction a ~ turn  c. clear in outline or detail ; distinct a ~ image  d. set forth with clarity and distinctness ~ 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  • ~ly adverb  • ~ness noun Synonyms:  ~, keen, acute mean having or showing alert competence and clear understanding. ~ implies quick perception, clever resourcefulness, or sometimes questionable trickiness ~ 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 ~ness of discrimination an acute sense of style.  II. adverb  Date: before 12th century  1. in a ~ manner  2. exactly 1:15 ~  III. noun  Date: 14th century one that is ~: as  a. a ~ 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 ~er  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 SHARP  biographical name Phillip Allen 1944- American biologist