What is the definition of plunge?

1. vti move suddenly downwards: to move suddenly downwards or forwards, or move something in this way * plunged into the undergrowth and disappeared 2. vt put somebody or something in difficulties: to put somebody or something suddenly into an unpleasant or undesirable situation 3. vt put something quickly into something: to put something quickly or firmly into something such as a liquid or container * Drain the beans and plunge them into cold water. 4. vi become involved enthusiastically: to become involved in something with great enthusiasm * She plunged into student life. 5. vi embark on reckless action: to begin a course of action suddenly and in a reckless or impetuous way * warned against plunging into hostilities without trying diplomacy first 6. vi descend precipitously: to descend abruptly or steeply * The mountains plunged to the sea. 7. vi drop suddenly in value: to drop suddenly and unexpectedly in value, price, or amount * Prices plunged. 8. vi gamble recklessly: to gamble, speculate, or take risks in a reckless way (informal) noun (plural plunges)

1. act of leaping into water: a dive or leap into water * a headlong plunge into the sea 2. sudden drop in value: a sudden unexpected drop in value, price, or amount * a 38 per cent plunge in PC sales 3. sudden rush: a sudden or violent rush * The dog made a plunge for the open door. 4. reckless gamble: a reckless gamble or speculation (informal) [14th century. Via Old French plongier < assumed Vulgar Latin plumbicare 'heave a sounding lead' < Latin plumbum 'lead'] take the plunge to commit suddenly to doing something new, difficult, or irrevocable to get married or decide to get married (informal humorous)