後牙 [后－]

Jyutping hau6 ngaa4
Pinyin hòu yá

Definitions (Wiktionary)
  1. verb, dialectal
    to argue pointlessly; to indulge in idle talk
  2. verb
    to grind one's teeth during sleep
  3. noun
    molar
    (syn.) 牙槽齿, 槽牙, 臼齒, 大牙, 臼齿, 牙槽齒