This is the 7089th most frequent French word.
menteur
Liar.
The word 'menteur' is used as a noun describing a person who lies frequently.
Il est un menteur qui invente souvent des histoires.
He is a liar who often makes up stories.
Here, 'menteuse' is the feminine form of 'menteur', used to describe a woman who lies often.
Elle était tellement menteuse qu'on ne pouvait pas lui faire confiance.
She was so deceitful that we couldn't trust her.
In this sentence, 'menteurs' is used adjectivally to describe the statements as deceitful or untruthful.