prognathism
noun [ U ] anatomy, medical specialized uk/ˈprɒɡ.nə.θɪ.zəm/ us/ˈprɑːɡ.nə.θɪ.zəm/
凸颌畸形，下颌前突
a condition in which the lower teeth go over the upper teeth when a person bites the teeth together; the fact of the lower jaw sticking out
See also: underbite