數典忘祖 [数－－－]

Jyutping sou2 din2 mong4 zou2
Pinyin shǔ diǎn wàng zǔ

Definitions (CC-CEDICT)
  1. to recount history but omit one's ancestors (idiom); to forget one's roots
Definitions (粵典–words.hk)
  1. 動詞
    對​自己​祖先​、​組織​或者​國​家​嘅​歷​史​缺乏​認識
    to lack understanding of the history of one's ancestors or country; to forget one's roots
Definitions (Wiktionary)
  1. phrase, idiomatic
    to be ignorant of the history of one's own country or ancestors
  2. phrase, idiomatic
    to forget one's roots
Definitions (Kaifangcidian)
  1. （沒有對應漢語詞彙）