Definition of plunge:
a brief swim in water
a steep and rapid fall
thrust or throw into; "Immerse yourself in hot water"
drop steeply; "the stock market plunged"
dash violently or with great speed or impetuosity; "She plunged at it eagerly"
begin with vigor; "He launched into a long diatribe"; "She plunged into a dangerous adventure"
cause to be immersed; "The professor plunged his students into the study of the Italian text"
fall abruptly; "It plunged to the bottom of the well"
immerse briefly into a liquid so as to wet, coat, or saturate; "dip the garment into the cleaning solution"; "dip the brush into the paint"
devote (oneself) fully to; "He immersed himself into his studies"