心配

1. Origins, structure, and basic meaning

• Structure: 心配 (しんぱい) is a noun that also forms a する verb for worry or concern that something may go wrong.
• Basic usage: A person of concern can take を in 弟を心配する, while 心配しなくてよい says that worrying is unnecessary.
  • 帰りが遅い弟を母が心配している。 — My mother is worried about my younger brother coming home late.
  • 明日の天気はそれほど心配しなくてよい。 — There is no need to worry much about tomorrow's weather.

2. Common pitfalls and similar expressions

• Object and degree of concern
  • The object of 心配する can take を. それほど心配しなくてよい means there is no need to worry that much, rather than asserting that no concern exists at all.