posthaste

With great speed; rapidly.

Great speed; rapidity.

Haste or speed like that of a post or courier in traveling.

With the haste of a post; with speed or urgent expedition: as, he traveled post-haste.

Expeditious; speedy; immediate.

[The edition of 1623 reads “post, post-haste.”]

Haste or speed in traveling, like that of a post or courier.

With speed or expedition

quickly, as fast as someone travelling post; with great speed

Alternative spelling of post-haste.