great · admirable

1. Origins, structure, and basic meaning

• Structure: 偉 conveys greatness or an admirable quality. 偉い is read えらい.
• Basic usage: 偉い can praise a person or action; 偉大(いだい) emphasizes greatness or a major achievement.

2. Common pitfalls and similar expressions

• The relationship in praise
  • 偉いね can praise a child or someone close. Because it evaluates the listener, using it directly to a superior can sound patronizing.
• Forms before nouns
  • Use い before the noun in 偉い人 and な in 偉大な成果.