Aback

toward the back.
Nautical. so that the wind presses against the forward side of the sail or sails.
(of a sail) positioned so that the wind presses against the forward side.
(of a yard) positioned so that its sail is laid aback.
taken aback, surprised and disconcerted:
I was taken aback by his harsh criticism.
Contemporary Examples

This has always put Arabs aback, made them vulnerable and eager to avoid uncalculated escalation.
The End Of Deterrence Nervana Mahmoud November 12, 2012

Historical Examples

An order well understood to mean, fill the main-topsail, after it has been aback, or the ship hove-to.
The Sailor’s Word-Book William Henry Smyth

Well, when you consider that, can you wonder I was set all aback?
Cap’n Warren’s Wards Joseph C. Lincoln

A word used in veering for aback, alluding to the situation of the head-yards in paying off.
The Sailor’s Word-Book William Henry Smyth

It took her aback by its directness, and for a moment left her without an answer.
The Snare Rafael Sabatini

This discovery knocked us all aback, and we were quite at a loss how to proceed.
Ned Myers James Fenimore Cooper

I certainly took him aback, and he almost dropped the glass.
Two Sides of the Face Arthur Thomas Quiller-Couch

And there she saw a thing that struck her so aback with amazement, that every timid sense was mute.
Cripps, the Carrier R. D. (Richard Doddridge) Blackmore

When he tried to come nearer her she laughed and thrust him aback.
Privy Seal Ford Madox Ford

His reply took me aback, until his sinister face broadened into a smile.
The Golden Face William Le Queux

adverb
taken aback

startled or disconcerted
(nautical) (of a vessel or sail) having the wind against the forward side so as to prevent forward motion

(rare) towards the back; backwards
adv.

c.1200, from Old English on bæc “at or on the back;” see back (n.). Now surviving mainly in taken aback, originally a nautical expression in reference to a vessel’s square sails when a sudden change of wind flattens them back against the masts and stops the forward motion of the ship (1754). The figurative sense is first recorded 1840.
see: take aback