with the greatest possible speed or promptness: to come to a friend's aid posthaste.


Archaic. great haste.

Origin of posthaste

First recorded in 1530–40; post3 + haste Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for posthaste

Historical Examples of posthaste

  • Didn't she send me posthaste with an umbrella 'cause she see a little cloud in the sky?


    Eleanor H. Porter

  • He accordingly sent his private secretary Biraga, posthaste to Spain with two letters.

  • The bearer on horseback, the horse in a foam—smoking like a boiler at the heat—be sure a posthaste letter!

    The Hunchback

    James Sheridan Knowles

  • Posthaste, two months since, came to the house outside Granada, the buyer for the London firm.

    The Wolf Cub

    Patrick Casey

  • It was as Rolfe had said, and the free and able-bodied of the plantations had put out, posthaste, for matrimony.

    To Have and To Hold

    Mary Johnston

British Dictionary definitions for posthaste



with great haste; as fast as possible


archaic great haste
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for posthaste

1590s, from a noun (1530s) meaning "great speed," usually said to be from "post haste" instruction formerly written on letters (attested from 1530s), from post (adv.) + haste (n.). The verb post "to ride or travel with great speed" is recorded from 1550s.

Online Etymology Dictionary, © 2010 Douglas Harper

posthaste in Culture



Immediately, with great speed: “Get the flood warning to the media posthaste.”

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.