To Crush
To Squash, To Ruin Something
transitive verb, godan verb
This word consists of kanji with hiragana attached. Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means crush or squash so the verb version is to crush or to squash.
潰す means to crush or smash something beyond repair. While it's often used literally, like 箱を潰す (flatten a box), it can also be used in figurative ways, like ruining a plan, killing time, blowing a chance, or even driving a business to bankruptcy.
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You learned that reading already with the kanji, so you should be all set here.
ものを潰す
to crush something
時間を潰す
to kill time
会社を潰す
to bankrupt a company
メンツを潰す
to make someone lose face
ニキビを潰す
to pop a pimple
暇を潰す
to kill free time
空き缶を足で潰した。
I crushed the empty can with my foot.
彼は虫を見て思わず潰してしまった。
He instinctively squashed the bug when he saw it.
予定が急に空いたので、時間を潰す必要ができちゃったんです。
My plans suddenly opened up, so I had to kill some time.
チャンスを潰すようなことばかりしてると、いつか会社も潰すことになるよ！
If you keep ruining every chance you get, you'll end up sinking the whole company someday!