plunging

Concise Oxford English Dictionary © 2008 Oxford University Press:
plunge/plʌnʤ/

▶verb

• 1 fall or move suddenly and uncontrollably.

  ■ jump or dive quickly and energetically.

  ■ (often plunge in) embark impetuously on a speech or course of action.

• 2 push or thrust quickly.

  ■ (plunge someone/thing into) suddenly bring someone or something into a specified condition or state.

▶noun an act of plunging.

– phrases
take the plunge informal commit oneself to a bold course of action after consideration.

– origin ME: from OFr. plungier ‘thrust down’, based on L. plumbum ‘lead, plummet’.