刎頸之交 [－颈－－]

Jyutping man5 geng2 zi1 gaau1
Pinyin wěn jǐng zhī jiāo

Definitions (Wiktionary)
  1. phrase, idiomatic
    friends sworn to death; eternal friends; best friends who can face hardships together
    (syn.) 刎颈交, 刎頸至交, 刎頸交, 刎颈至交