sharpen

verb

Etymology: From Middle English scharpenen, scharpnen, equivalent to sharp + -en.

1. To make sharp.

   “to sharpen a pencil or a knife or a musical note”

   “He that wrestles with us strengthens our nerves and sharpens our skill.”

2. To become sharp.

   “The organizers said they had found themselves "more involved in the web of social convulsions and violence that is tormenting our country. The present economic crisis, the grave political instability and the rapidly sharpening violence have finally overtaken […] our wishes.”