lower mouth noun3 •The lower jaw.Her top fillings had crumbled into a powder and had fallen out. Some in her lower mouth had become embedded in the gums and extensive dental work was needed to sort her out. — 1997 •The lower lip.This young man - whose face was steak from his upper right eye socket to the corner of his lower mouth - uttered one day after his wound had been dressed the sound ‘A’her ease nur’. — 2012 •(euphemistic) The vulva.At last, in desperation, he began to give her what she wanted. His teeth, lips, and tongue serviced her hungry lower mouth with abandon. She moaned with pleasure every time his teeth scraped her clit. — 1989 formslower mouths