Formal:
* Forte: This is the most common and general word for "strong".
* Robusto: This means "robust" or "sturdy", implying strength and durability.
* Vigoroso: This means "vigorous" and implies strength and energy.
Informal:
* Força: This is the noun for "strength", but can be used informally to mean "strong".
* Brabo: This is a slang term for "strong" or "powerful", often used in a playful or admiring way.
Other possibilities:
* Poderosa/o (powerful)
* Resistente (resistant)
* Firme (firm)
Examples:
* Ele é um homem forte. (He is a strong man.)
* Esta madeira é muito robusta. (This wood is very sturdy.)
* O motor do carro é muito vigoroso. (The car's engine is very powerful.)
* Ela é forte e independente. (She is strong and independent.)
* Essa música é muito braba! (That music is really strong!)
The best way to choose the right word will depend on the specific situation and the level of formality required.