plunger: Meaning and Definition of

plung•er

1. a pistonlike reciprocating part moving within the cylinder of a pump or hydraulic device.
2. a pistonlike part in the valve of a pneumatic tire.
3. Also calleda device consisting of a handle with a rubber suction cup at one end, used as a force pump to free clogged drains and toilet traps.
4. a person or thing that plunges.
5. a reckless bettor or speculator.