How to Say "unable" in Spanish
The Spanish word for “unable” is “incapaz” — B1 level. This is a very common word in everyday Spanish.
English → SpanishB1
AdjectiveB1
cannot do something

Examples
Soy incapaz de concentrarme con tanto ruido.
I am unable to concentrate with so much noise.
Ella era incapaz de mentir, siempre decía la verdad.
She was incapable of lying; she always told the truth.
El sistema se demostró incapaz de manejar la demanda.
The system proved incapable of handling the demand.
Using 'de' after incapaz
When you want to say what someone is unable to do, you must always follow 'incapaz' with the preposition 'de' and then the action word (infinitive): 'incapaz de cocinar'.
Forgetting the preposition
Mistake: “Soy incapaz hacer esto.”
Correction: Soy incapaz **de** hacer esto. (Always include 'de' before the action.)
Related Translations
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