1. That new boy always looks sharp as a tack in class.
2. Tom is sharp as a tack; he got 100 on every test.
When Mum died at nintey she was still as sharp as a tack. Everything else wore out.
1. That new boy always looks sharp as a tack in class.
2. Tom is sharp as a tack; he got 100 on every test.
... an easy manner you sharp as a tack and we joked around ...