Formal:
* Бесстрашный (besstrashnyy): This is the most direct translation, meaning "without fear". It's a bit more formal and literary.
* Неустрашимый (neustrashimyy): This means "unfearing" and carries a sense of courage and determination.
* Отважный (otvazhyy): This word emphasizes bravery and boldness, implying a willingness to face danger.
Informal:
* Смелый (smelyy): This means "brave" and is a more common, everyday word for describing someone who is not afraid.
* Храбрый (khrabryy): This also means "brave" but has a slightly more positive and heroic connotation.
Other options:
* Не боящийся (ne boyashchiysya): This literally means "not afraid" and is a more neutral option.
* Не испытывающий страха (ne ispytyvayushchiy strakha): This translates to "not experiencing fear" and is quite formal.
Example:
* "The pilot was бесстрашный (besstrashnyy) and landed the plane safely."
* "The soldier was отважный (otvazhyy) and fought bravely."
* "She was a смелая (smelaya) woman and stood up for what she believed in."
The best word to use will depend on the specific context and the overall tone you want to convey.