1Having a projecting lower jaw or chin.
- 1.1(of a lower jaw or chin) projecting.‘her chin was a little prognathous’
- ‘Enlarged as though in a magnifying mirror, the abundant follicles sprout gut-string stubble as a gentle sleeping smile winks above the prognathous jaw.’
- ‘Exceedingly tall and gaunt with a long, prognathous jaw, he never took his eyes from me as he went over to an accordion wilted across a stool.’
- ‘Although the head is worn, a detail shows that the lower part of the face extends down to the trachea at the base of the neck; this roughened area, too massive to be simply a prognathous jaw, must instead represent a full beard.’
- ‘The prognathous jaw became a sign of lower development and of a closer relationship to primitive man.’
- 1.1(of a lower jaw or chin) projecting.
Mid 19th century: from pro- ‘before’ + Greek gnathos jaw + -ous.