IPA: //ˈpoʊstˌheɪst//
KK: /ˈpoʊstˌheɪst/
In a very quick manner; doing something as fast as possible.
She left the office posthaste to catch her flight.
A term used to describe doing something very quickly or with great speed.
He completed the project posthaste to meet the deadline.
Posthaste → It is formed from "post" (from Latin *post*, meaning after) and "haste" (from Old French *haste*, meaning speed or urgency). The term originally referred to traveling with great speed after a message or order.
Think of 'after' ('post') and 'speed' ('haste') to remember that 'posthaste' means to do something with great urgency or speed.