From the former instruction on letters ‘haste, post, haste’, later reinterpreted as a compound of post + haste.
posthaste (not comparable)
- quickly, as fast as someone travelling post; with great speed
- It is imperative that you finish your task posthaste.
- 1946 — Paramahansa Yogananda, Autobiography of a Yogi, Ch. 17
- "Sasi cannot last through the night." These words from his physician, and the spectacle of my friend, now reduced almost to a skeleton, sent me posthaste to Serampore.
- Alternative spelling of post-haste.
- 1602 : Hamlet by William Shakespeare, act 1 scene 1 l 103-106
- "And this, I take it,
- Is the main motive of our preparations
- The source of this our watch, and the chief head
- Of this post-haste and rummage in the land."