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

(11) Why did they not bring four witnesses to prove it? When they have not brought the witnesses, such men, in the sight of Allah, (stand forth) themselves as liars!

(12) (Allah will say): "Now have they proved you liars in what ye say: so ye cannot avert (your penalty) nor (get) help." And whoever among you does wrong, him shall We cause to taste of a grievous Penalty.

(13) "Thou art no more than a mortal like us, and indeed we think thou art a liar!

(14) (Into whose ears) they pour hearsay vanities, and most of them are liars.

(15) Pharaoh said: "O Chiefs! no god do I know for you but myself: therefore, O Haman! light me a (kiln to bake bricks) out of clay, and build me a lofty palace, that I may mount up to the god of Moses: but as far as I am concerned, I think (Moses) is a liar!"

(16) And the Unbelievers say to those who believe: "Follow our path, and we will bear (the consequences) of your faults." Never in the least will they bear their faults: in fact they are liars!

(17) O ye who believe! Enter not the Prophet's houses,- until leave is given you,- for a meal, (and then) not (so early as) to wait for its preparation: but when ye are invited, enter; and when ye have taken your meal, disperse, without seeking familiar talk. Such (behaviour) annoys the Prophet: he is ashamed to dismiss you, but Allah is not ashamed (to tell you) the truth. And when ye ask (his ladies) for anything ye want, ask them from before a screen: that makes for greater purity for your hearts and for theirs. Nor is it right for you that ye should annoy Allah's Messenger, or that ye should marry his widows after him at any time. Truly such a thing is in Allah's sight an enormity.

(18) "Allah has begotten children"? but they are liars!

(19) A believer, a man from among the people of Pharaoh, who had concealed his faith, said: "Will ye slay a man because he says, 'My Lord is Allah'?- when he has indeed come to you with Clear (Signs) from your Lord? and if he be a liar, on him is (the sin of) his lie: but, if he is telling the Truth, then will fall on you something of the (calamity) of which he warns you: Truly Allah guides not one who transgresses and lies!

(20) "The ways and means of (reaching) the heavens, and that I may mount up to the god of Moses: But as far as I am concerned, I think (Moses) is a liar!" Thus was made alluring, in Pharaoh's eyes, the evil of his deeds, and he was hindered from the Path; and the plot of Pharaoh led to nothing but perdition (for him).