泣き出す

1. Origins, structure, and basic meaning

• Structure: 泣き出す(なきだす) combines 泣き, from 泣く, with 出す to express starting to cry.
• Basic usage: It depicts a child suddenly starting to cry upon finding their mother.
  • 迷子の子どもは母親を見つけると急に泣き出した。

2. Common pitfalls and similar expressions

• How the crying begins
  • 泣き始める(なきはじめる) also means to start crying. 泣き出す readily conveys the sense of tears suddenly breaking out.