The Spanish verb 'mentir' (to lie) comes directly from the Latin verb 'mentiri', which meant 'to lie' or 'to deceive'. This is a straightforward inheritance where both the form and meaning have remained remarkably stable over time, with just the typical Latin-to-Spanish sound changes affecting the ending (-iri > -ir).

Some related Spanish words that might help you remember 'mentir' include 'mentira' (a lie/falsehood), 'mentiroso' (liar), and 'desmentir' (to contradict or deny). All these words share the root 'ment-' and relate to the concept of falsehood or deception.

While English doesn't have any common words directly related to 'mentir', you might encounter some formal or technical terms that share this Latin root, such as 'mendacious' (not truthful, lying) and 'mendacity' (untruthfulness). However, these are rather formal words and not commonly used in everyday English.