From Longman Dictionary of Contemporary Englishliarli‧ar /ˈlaɪə $ -ər/ ●●○ noun [countable] LIE/TELL A LIEsomeone who deliberately says things which are not true Are you calling me a liar?COLLOCATIONSadjectivesa good liar (also an accomplished liar formal) (=someone who tells believable lies)He's an accomplished liar who lies as easily as other men breathe.a terrible/poor/rotten liar (=who does not tell believable lies)You're a rotten liar, Julia. What really happened?a big liar spoken (=someone who tells big lies)You're such a big liar!a habitual/chronic/inveterate liar formal (=who lies a lot)Drug users are often habitual liars trying to cover up their addiction.a congenital/pathological/compulsive liar formal (=who tells lies because it is part of their personality to do so)He called her a congenital liar who would say anything to stay out of trouble.verbscall somebody a liar (=say that someone is lying)Are you calling my mother a liar?accuse somebody of being a liarHe accused me of being a liar.
Examples from the Corpus
liar• But I don't think you're quite as good a liar as you think you are.• She may be stupid, but she's not a liar.• For Hugh the world was almost chock-full of traitors and liars and fools.• Of course, in that environment, being a congenital liar was small potatoes.• He can't possibly be a scientist and at the same time such a dreadful liar.• Coleman described the president as a "pathological liar" and "a criminal in the White House."• We condemn the liar, blame the cheat, and excuse innocent error. 