• make sharp, make pointed; be sharpened
• if you sharpen an object, you make its edge very thin or you make its end pointed.
• if your senses or abilities sharpen or if you sharpen them, you become quicker at thinking or at noticing things, or better at your particular skill.
• if disagreements or differences between people sharpen or if something sharpens them, they increase; a formal use.
• if your voice sharpens or if you sharpen it, you begin to speak more angrily and quickly.
• if you sharpen a knife or other tool up, you make its edge thinner or make its end more pointed.
• if someone sharpens up their image, performance, or opinion, or if it sharpens up, it becomes better or more clearly defined.