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

(1) Yea, in their own (eyes) will become manifest what before they concealed. But if they were returned, they would certainly relapse to the things they were forbidden, for they are indeed liars.

(2) The leaders of the Unbelievers among his people said: "Ah! we see thou art an imbecile!" and "We think thou art a liar!"

(3) Allah give thee grace! why didst thou grant them until those who told the truth were seen by thee in a clear light, and thou hadst proved the liars?

(4) And there are those who put up a mosque by way of mischief and infidelity - to disunite the Believers - and in preparation for one who warred against Allah and His Messenger aforetime. They will indeed swear that their intention is nothing but good; But Allah doth declare that they are certainly liars.

(5) But the chiefs of the Unbelievers among his people said: "We see (in) thee nothing but a man like ourselves: Nor do we see that any follow thee but the meanest among us, in judgment immature: Nor do we see in you (all) any merit above us: in fact we think ye are liars!"

(6) "And O my people! Do whatever ye can: I will do (my part): Soon will ye know who it is on whom descends the penalty of ignominy; and who is a liar! and watch ye! for I too am watching with you!"

(7) He said: "It was she that sought to seduce me - from my (true) self." And one of her household saw (this) and bore witness, (thus):- "If it be that his shirt is rent from the front, then is her tale true, and he is a liar!

(8) "But if it be that his shirt is torn from the back, then is she the liar, and he is telling the truth!"

(9) (Respite will be granted) until, when the messengers give up hope (of their people) and (come to) think that they were treated as liars, there reaches them Our help, and those whom We will are delivered into safety. But never will be warded off our punishment from those who are in sin.

(10) When those who gave partners to Allah will see their "partners", they will say: "Our Lord! these are our 'partners,' those whom we used to invoke besides Thee." But they will throw back their word at them (and say): "Indeed ye are liars!"