Taken aback

Originally, this was a nautical term dating from the late 1600s, and possibly before, for when a sudden gust of wind came from straight ahead would set the sails back against the masts. This would, of course, halt the forward motion of a sailing ship, and the sails and the ship would literally be ‘taken aback’. The figurative meaning as in surprised or disconcerted by any sudden change of events dates from the early 19th century, as does the expression, ‘take the wind out of someone’s sails’, which means more or less the same thing and derives from the same source.