The word(s) "backs" appears 26 time(s) in 25 verse(s) in Quran in Abdullah Yusuf Ali translation.

(21) O ye who believe! Avoid suspicion as much (as possible): for suspicion in some cases is a sin: And spy not on each other behind their backs. Would any of you like to eat the flesh of his dead brother? Nay, ye would abhor it... But fear Allah: For Allah is Oft-Returning, Most Merciful.

(22) Soon will their multitude be put to flight, and they will show their backs.

(23) If they are expelled, never will they go out with them; and if they are attacked (in fight), they will never help them; and if they do help them, they will turn their backs; so they will receive no help.

(24) Inviting (all) such as turn their backs and turn away their faces (from the Right).

(25) Who give the lie to Truth and turn their backs.