POSTHASTE Definition Meaning - Merriam-Webster In the 16th century, the phrase "haste, post, haste" was used to inform posts (as couriers were then called) that a letter was urgent and must be hastily delivered
Posthaste: History and Meaning | Merriam-Webster You may think 'posthaste' is somehow related to the prefix 'post' meaning 'after,' but rather it is related to the postal service, where 'post, haste' meant to deliver a letter as fast as possible