não sei
/ˈnɐ̃w̃ ˈsej/
In Portuguese, "I don't know" is said as não sei.
Não sei is a straightforward and neutral way to express not knowing something in a formal situation. For a stronger emphasis, you can say Não tenho a menor ideia to mean "I have no idea whatsoever," or Não fazia a mínima ideia to say "I had absolutely no idea." You might also use the phrase Não faço a menor ideia do que você está falando if you want to say "I have no idea what you're talking about."
Meaning: I don’t know (intj)
How does it change in a sentence?
In the phrase não sei, the subject Eu (I) is often omitted because the verb conjugation sei already indicates the first person singular.
How do you pronounce it?
/ˈnɐ̃w̃ ˈsej/
Did you know?
- The verb in não sei comes from the verb 'saber', which shares a common ancestor with the English word 'sapient' (meaning wise/knowing).
- In many informal Brazilian Portuguese settings, instead of saying não sei, people might simply shrug and say sei lá.
- A common non-verbal accompaniment to não sei in Brazil is a slight shrug accompanied by a clicking sound made with the tongue against the roof of the mouth.
Examples in context
- Eu já não sei.I don't know anymore.This sentence is useful for expressing that you no longer know something using não sei.Tatoeba #7089908 by alexmarcelo, translation #6900628 by kaiperkins271
- Não sei quem é.I don't know who he is.This sentence shows how to use não sei to indicate you do not know a specific person.Tatoeba #1396789 by alexmarcelo, translation #260118 by CK
- Eu não sei nada.I don't know anything.This sentence demonstrates using não sei to say you do not know anything.Tatoeba #1212955 by alexmarcelo, translation #370605 by saeb
- 1374 more sentences on Tatoeba
Example conversation
Felipe and Beatriz are looking for their keys.
- FelipeVocê viu as minhas chaves, Beatriz?Have you seen my keys, Beatriz?
- BeatrizEu não sei, Felipe.I don't know, Felipe.
- FelipeSerá que estão na mesa?Could they be on the table?
- BeatrizEu não sei, olhe lá.I don't know, look there.
Sources
- Wiktionary, “I don't know” translations and entries não sei, CC BY-SA 4.0, dump of 2026-09-26.
- Word origins: Wiktionary entries não, CC BY-SA 4.0.
- Example sentences: Tatoeba CC BY 2.0 FR.
