猛烈

1. Origins, structure, and basic meaning

• Structure: 猛烈, read もうれつ, is a na-adjectival stem for fierce or intense force.
• Basic usage: 猛烈な風 directly modifies a fierce wind; 猛烈に働く adverbially intensifies the work.

2. Common pitfalls and similar expressions

• 猛烈な before nouns and 猛烈に before verbs
  • Use な to modify a noun and に to modify an action. One describes the wind's quality and the other how people worked.