smart as a whip
Very intelligent or clever, as in Little Brian is smart as a whip; he's only three and already learning to read. This simile alludes to the sharp crack of a whip. [Mid-1900s] Also see mind like a steel trap.
Read more in this article about some frequently asked questions and fun facts related to our definitions.
Is There Such A Thing As A True Synonym?
Thesauruses present a catalog of synonyms from which we may pick and choose words to put into our writing, but a thesaurus used alone is a very bad thing because there is no such thing as a true synonym. Every word has its particular place in the language.
vigorous, effective, deft, able, active, wise, ready, sharp, keen, knowing, acute, prompt, slick, adept, whiz, savvy, adroit, apt, astute, bright
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.