falling steeply

marvel at plunging waterfalls, hanging valleys, and secluded beaches

a plunging ravine

(of a neckline on a woman's garment) very low-cut

form-fitting dresses with plunging necklines

a plunging V-neck

jump or dive quickly and energetically

our little daughters whooped as they plunged into the sea

push or thrust quickly

he plunged his hands into his pockets