How to Say "dumbass" in Spanish
The Spanish word for “dumbass” is “pendejo” — C1 level. This is a very common word in everyday Spanish.

Examples
¡No seas pendejo! Esa oferta es una estafa.
Don't be an idiot! That offer is a scam.
Ese pendejo me chocó el coche y se fue.
That jerk hit my car and drove away.
Me siento como un pendejo por haber creído su mentira.
I feel like a dumbass for believing his lie.
Using it as a label vs. description
You can use this word as a label ('un pendejo') or as a describing word ('él es muy pendejo'). It changes to 'pendeja' when talking about a female.
Softening with 'ser'
When used with 'no seas' (don't be), it is often a warning to a friend, whereas 'él es' (he is) is a direct insult.
High Offense Risk
Mistake: “Using this word with people you don't know well.”
Correction: Only use this word with very close friends in casual settings, or avoid it entirely, as it is a strong swear word in many countries.
Related Translations
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