How to Say "merciless" in Spanish
The Spanish word for “merciless” is “cruel” — B1 level. This is a very common word in everyday Spanish.

Examples
El dictador era conocido por sus métodos crueles.
The dictator was known for his cruel methods.
La vida a veces puede ser muy cruel e injusta.
Life can sometimes be very harsh and unfair.
Fue un comentario cruel que hirió sus sentimientos.
It was a cruel comment that hurt her feelings.
Gender is Invariable
Unlike many Spanish adjectives, 'cruel' is the same for both masculine and feminine nouns. You say 'el hombre cruel' (the cruel man) and 'la mujer cruel' (the cruel woman).
Forgetting the Plural
Mistake: “Los jefes cruel.”
Correction: The correct plural is 'crueles': Los jefes crueles. Adjectives ending in a consonant add '-es' to become plural.
Learn Spanish with Inklingo
Interactive stories, personalized learning, and more.