What does posthaste mean?
Posthaste means with all possible speed, emphasizing unusually urgent or rapid action. It is commonly used in stories, reports, and formal prose to describe a person or thing moving, working, or completing a task with exceptional haste. The expression can suggest determination and efficiency, but it may also carry a humorous or exaggerated tone, as though the speed is so great that it demands special attention. In older and literary usage, “posthaste” can stand before a noun, as in “a posthaste journey,” meaning that something is undertaken with great speed. Although still understood in British and American English, it is not usually the first choice for ordinary contemporary speech, where a simpler term such as “quickly,” “rapidly,” or “as fast as possible” may be preferable. The word is especially effective in narrative writing when a character is racing against time.
With all possible speed; as quickly as possible.
"They drove posthaste to reach the airport before the flight departed."
Now chiefly literary, formal, or jocular rather than neutral everyday usage.
Done, undertaken, or completed with the greatest possible speed.
"The report described the escape as a posthaste flight from the city."
This attributive use is relatively rare and sounds literary or archaic.
Once a command to travel with all possible speed, “posthaste” now adds dramatic urgency to reports of rushed journeys and hurried actions.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does posthaste come from?
“Posthaste” is a compound of “post” and “haste,” both of Old French origin. “Post” originally meant “after” or “behind,” while “haste” derives from Old French “hast,” from a Germanic root associated with speed. The expression developed in the late medieval or early modern period to mean “with all possible speed” and was later established in its modern hyphenated form.
Related word forms
How posthaste is actually used
The adverb is chiefly literary, formal, or occasionally jocular in modern English; “quickly” and “as fast as possible” are more neutral alternatives. Its attributive use is rarer and sounds more archaic.