v.
- fall or move suddenly and uncontrollably.
▸jump or dive quickly and energetically.
▸
(often plunge in)
embark impetuously on a speech or course of action.
- push or thrust quickly.
▸
(plunge someone/thing into)
suddenly bring someone or something into a specified condition or state.
n.
an act of plunging.
Phrase
- take the plunge
informal commit oneself to a bold course of action after consideration.
Etymology
ME: from OFr. plungier ‘thrust down’, based on L. plumbum ‘lead, plummet’.