1 [intransitive and transitive]
to make something have a sharper edge or point:
Anne sharpened her pencil and got out her homework.
to make a feeling stronger and more urgent:
A series of attacks have sharpened fears of more violence.
3 [transitive] also sharpen something ↔ up
to improve something so that it is up to the necessary standard, quality etc:
The course will help students sharpen their writing skills.