adj

• (colloquial) Intelligent.
  "My nephew is a sharp lad; he can count to 100 in six languages, and he's only five years old."
• (music) Raised by one semitone (denoted by the symbol ♯ after the name of the note).
• (music) Higher in pitch than required.
  "The orchestra's third violin several times was sharp about an eighth of a tone."
• (colloquial) Illegal or dishonest.
  "Michael had a number of sharp ventures that he kept off the books."

adv

• (of times of day, not comparable) Exactly.
  "I'll see you at twelve o'clock sharp."
• (music) In a higher pitch than is correct or desirable.
  "I didn't enjoy the concert much because the soprano sang sharp on all the high notes."

noun

• (music) The symbol ♯, placed after the name of a note in the key signature or before a note on the staff to indicate that the note is to be played one chromatic semitone higher.
  "The pitch pipe sounded out a perfect F♯ (F sharp)."
• (music) A note that is played one chromatic semitone higher than usual; denoted by the name of the note that is followed by the symbol ♯.
• (music) A note that is sharp in a particular key.
  "The piece was difficult to read after it had been transposed, since in the new key many notes were sharps."
• (music) The scale having a particular sharp note as its tonic.
  "Beethoven's "Moonlight Sonata" is written in C♯ minor (C sharp minor.)"

verb

• (music) To raise the pitch of a note half a step making a natural note a sharp.
  "That new musician must be tone deaf: he sharped half the notes of the song!"
• (transitive, obsolete) To sharpen.