Mentiroso vs. embustero
The Spanish words mentiroso and embustero both translate to the English word liar. Although they are synonyms, they differ slightly in their connotations and are used in slightly different contexts.
Mentiroso
A2Mentiroso directly translates to liar in English, referring to someone who tells untruths frequently.
No creo nada de lo que dice, es un mentiroso.
(I don't believe anything he says, he's a liar.)
No seas mentiroso, cuéntame la verdad.
(Don't be a liar, tell me the truth.)
Embustero
B2Embustero is also translated as liar, but it carries a stronger connotation. It often refers to someone who is crafty or manipulative in their lies.
Él es un embustero y siempre intenta engañarme con sus historias falsas.
(He is a deceiver and always tries to fool me with his fake stories.)
¡No le escuches, es un embustero!
(Don't listen to him, he's a trickster!)
Summary
Mentiroso and embustero in Spanish both refer to an individual who lies. However, while mentiroso refers to any individual who lies, embustero refers more specifically to an individual who is deceitful or crafty in their lies.