sharpen
v.
1520s, "bring to an edge or point," from sharp, adj. + -en(1). Related: Sharpened; sharpening. Old English verb scearpian meant "to score, scarify;" also compare scearpung "scarifying." To sharpen (one's) pencil "prepare to get to work" is from 1957, American English.
〔李〕[sharp a. 尖的，锋利的；-en →] v. cause to be sharp；make sharper削尖，磨快