plunger
https://gyazo.com/fceb503f43c9b0d05407dac566e1c132
日本語だとラバーカップというらしい
すっぽん
https://gyazo.com/215f5b75a10d30afa2682a6e7abbf459
noun
a part of a device or mechanism that works with a plunging or thrusting movement.
2. informal a person who gambles or spends money recklessly.
⦅くだけて⦆ 無謀な博打(ばくち)打ち[相場師].