DICT.TW Dictionary Taiwan

 Sharp·en v. t. [imp. & p. p. Sarpened p. pr. & vb. n. Sharpening.]  To make sharp. Specifically: (a) To give a keen edge or fine point to; to make sharper; as, to sharpen an ax, or the teeth of a saw. (b) To render more quick or acute in perception; to make more ready or ingenious.
 The air . . . sharpened his visual ray
 To objects distant far.   --Milton.
    He that wrestles with us strengthens our nerves and sharpens our skill.   --Burke.
 (c) To make more eager; as, to sharpen men's desires.
 Epicurean cooks
 Sharpen with cloyless sauce his appetite.   --Shak.
 (d) To make more pungent and intense; as, to sharpen a pain or disease. (e) To make biting, sarcastic, or severe. “Sharpen each word.” --E. Smith. (f) To render more shrill or piercing.
    Inclosures not only preserve sound, but increase and sharpen it.   --Bacon.
 (g) To make more tart or acid; to make sour; as, the rays of the sun sharpen vinegar. (h) Mus. To raise, as a sound, by means of a sharp; to apply a sharp to.