This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

adj. Angled rearward from the points of attachment. Used especially of aircraft wings.

adj. Having wings of this type. Used of an aircraft.

adj. angled backwards from its attachment to the fuselage

adj. backswept

adj. (especially of aircraft wings) angled rearward from the point of attachment

adj. used of hair

"The broad-shouldered man, with dark sweptback hair, was wearing a slick suit, its color a blue just the regal side of navy and therefore suggestive of a uniform."

swept    backward   

setback   

sweptback wing