Meaning

noun a person who has lied or who lies repeatedly

originInherited from Middle English lier, liere, lyere, liȝer, lieȝer, legher, from Old English lēgere, lēogere (“liar, false witness, hypocrite”), from Proto-West Germanic *leugārī, from Proto-Germanic *leugārijaz (“liar”), from *leuganą (“to lie”) + *-ārijaz, equivalent to lie + -ar. More at lie.

Etymology from Wiktionary, CC BY-SA 3.0