笑う

1. Origins, structure, and basic meaning

• Structure: 笑う is read わらう and describes laughing.
• Basic usage: It ranges from a baby's laughter to laughing at someone else's failure; the target and situation determine the nature of the laughter.

2. Common pitfalls and similar expressions

• Meaning with an object
  • 失敗を笑う means making failure an object of ridicule. This differs in attitude from laughing with joy.
• Conjugation
  • The forms are 笑う → 笑って → 笑った.