Describes a person, action, or attitude showing courage and fearlessness. Often used in formal or literary contexts, but also common in everyday praise.
He bravely jumped into the fire.
勇敢な行動が多くの人を救った。
The courageous act saved many people.
He is known as a brave man.
The firefighters bravely went into the flames.
勇敢 describes a brave character or a heroic act (adjectival), whereas 勇気 names the inner quality of courage itself.
勇敢 describes straightforward bravery and is usually positive, whereas 不敵 can carry a nuance of audacity or recklessness that 勇敢 lacks.
勇敢 is an adjective describing brave conduct in general, while 武勇 is a noun tied specifically to martial valor.
勇敢 means brave in a straightforward, heroic sense when facing danger, while 健気 emphasizes an earnest, touching effort made despite weakness or hardship.