Possible Definitions:
1. Sharpen (a.) To make sharp.
2. Sharpen (a.) To give a keen edge or fine point to; to make sharper; as, to sharpen an ax, or the teeth of a saw.
3. Sharpen (a.) To render more quick or acute in perception; to make more ready or ingenious.
4. Sharpen (a.) To make more eager; as, to sharpen men's desires.
5. Sharpen (a.) To make more pungent and intense; as, to sharpen a pain or disease.
6. Sharpen (a.) To make biting, sarcastic, or severe.
7. Sharpen (a.) To render more shrill or piercing.
8. Sharpen (a.) To make more tart or acid; to make sour; as, the rays of the sun sharpen vinegar.
9. Sharpen (a.) To raise, as a sound, by means of a sharp; to apply a sharp to.
10. Sharpen (v. i.) To grow or become sharp.