Dictionary.com
definitions

posthaste

[ pohst-heyst ]
/ ˈpoʊstˈheɪst /
|
SEE MORE SYNONYMS FOR posthaste ON THESAURUS.COM

adverb

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

noun

Archaic. great haste.

RELATED WORDS

breakneck, directly, expeditious, flat-out, fleet, hastily, hasty, headlong, lickety-split, pell-mell, promptly, pronto, quick, quickly, rapid, rapidly, speedily, speedy, swift, swiftly

Nearby words

postganglionic motor neuron, postgastrectomy syndrome, postglacial, postgrad, postgraduate, posthaste, postheat, posthepatitic cirrhosis, posthioplasty, posthitis, posthole

Origin of posthaste

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

Examples from the Web for posthaste

British Dictionary definitions for posthaste

posthaste

/ (ˈpəʊstˈheɪst) /

adverb

with great haste; as fast as possible

noun

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

posthaste

adv.

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

Culture definitions for posthaste

posthaste

[ (pohst-hayst) ]

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.