Available Definitions:
1) v. i. - To plunge into water head foremost; to thrust the body under, or deeply into, water or other fluid.
2) v. i. - Fig.: To plunge or to go deeply into any subject, question, business, etc.; to penetrate; to explore.
3) v. t. - To plunge (a person or thing) into water; to dip; to duck.
4) v. t. - To explore by diving; to plunge into.
5) n. - A plunge headforemost into water, the act of one who dives, literally or figuratively.
6) n. - A place of low resort.