死黨 [－党]

Jyutping sei2 dong2
Pinyin sǐ dǎng

Definitions (CC-CEDICT)
  1. best friends
  2. inseparable sidekick
  3. diehard followers
Definitions (粵典–words.hk)
  1. 名詞
    最好​嘅​朋友​（​量​詞​：​個​/​班​）
    good friend; close friend; bosom buddy; one's best and most loyal friend; faithful partner. Literally: die party
  2. 近義詞
    摯友、老死
Definitions (Wiktionary)
  1. noun
    diehard reactionary clique
  2. noun, slang
    diehard followers; inseparable sidekick; best friends; people who ride or die
Definitions (Kaifangcidian)
  1. （沒有對應漢語詞彙）
  2. 老朋友
  3. 要好的朋友