sharp as a tack

(as) sharp as a tack

Intelligent and a quick-thinker. Ted's as sharp as a tack, so he'll find a solution to this problem. Of course Ellen is our valedictorian—she's as sharp as a tack.

See also: sharp, tack

sharp as a tack

Also, sharp as a razor. Mentally acute. For example, She's very witty-she's sharp as a tack. These similes are also used literally to mean "having a keen cutting edge" and have largely replaced the earlier sharp as a needle or thorn. The first dates from about 1900, the variant from the mid-1800s.

See also: sharp, tack

(as) sharp as a ˈtack

(American English) intelligent with a quick and lively mind: My grandmother’s 85 but she’s still sharp as tack.

A tack is a kind of small nail or pin.

See also: sharp, tack