How to Say "falsehood" in Spanish
The most common Spanish word for “falsehood” is “mentira” — use 'mentira' when referring to a specific untruth or a lie told by someone, especially in everyday conversation..
mentira
men-TEE-rah/menˈtiɾa/

Examples
No puedes confiar en él, siempre dice mentiras.
You can't trust him, he always tells lies.
Descubrimos que toda su historia era una mentira.
We discovered that his entire story was a falsehood.
¡Qué mentira tan grande me contaste!
What a big lie you told me!
Gender Rule
As a noun ending in -a, 'mentira' is always feminine. Use 'la' before it, or 'una' if you are referring to one lie.
Using the Verb vs. the Noun
Mistake: “I lie = *Yo soy mentira.* (Incorrect: This means 'I am a lie'.)”
Correction: The action of lying uses the verb *mentir*: *Yo miento.* (I lie.)
falsa
/fal-sa//ˈfalsa/

Examples
Su vida estaba construida sobre una falsa.
Her life was built upon a falsehood.
Noun Use
When used as a noun, 'falsa' usually refers to the abstract concept of untruth, rather than a specific spoken lie (for which you would use 'mentira').
Mentira vs. Falsa
Related Translations
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