*sharpen*

v. t. [ imp. & p. p. Sarpened p. pr. & vb. n. Sharpening. ] [ See Sharp, a. ] 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. [ 1913 Webster ]

The air . . . sharpened his visual ray
To objects distant far. Milton. [ 1913 Webster ]

He that wrestles with us strengthens our nerves and sharpens our skill. Burke. [ 1913 Webster ]

(c) To make more eager; as, to sharpen men's desires. [ 1913 Webster ]

Epicurean cooks
Sharpen with cloyless sauce his appetite. Shak. [ 1913 Webster ]

(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. [ 1913 Webster ]

Inclosures not only preserve sound, but increase and sharpen it. Bacon. [ 1913 Webster ]

(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. [ 1913 Webster ]