sharpener

sharpen +‎ -er

sharpener (plural sharpeners)

1. A device for making things sharp.

   There was a pencil sharpener at the front of the classroom.

2. (figuratively) That which makes something sharp.
   • Hannah More, The Shepherd of Salisbury Plain

     “Sir,” said the shepherd, “poverty is a great sharpener of the wits. […]

   • 1872, Chambers's miscellany of instructive & entertaining tracts

     The snuff-box, knife, and chicken-bones were again in requisition, and a pen was successfully formed. The ink, or at least its substitute, was rather more difficult, but necessity is always a sharpener of intellect, and even this was accomplished.

• sharp
• pencil sharpener

• resharpen