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. My granddad may be old and cantankerous, but he's still sharp as a tack. You can't get anything past him.
Farlex Dictionary of Idioms. © 2022 Farlex, Inc, all rights reserved.
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.
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
(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.
Farlex Partner Idioms Dictionary © Farlex 2017
sharp as a tack
Singularly keen or cutting; also, mentally acute. This simile has largely supplanted the earlier sharp as a razor, needle, vinegar, and thorn, the last dating from the fifteenth century and appearing in John Ray’s 1670 proverb collection. The current cliché dates from the late nineteenth or early twentieth century and appeared in a 1912 issue of Dialect Notes: “They won’t fool him; he’s sharp as tacks.”
The Dictionary of Clichés by Christine Ammer Copyright © 2013 by Christine Ammer