The 'x' mark used to indicate a wrong answer or to denote something as incorrect; commonly used in tests and everyday contexts to mark negatives.
テストのこの問題にはばつが付いていた。
This question on the test was marked with an X (wrong).
申し込みの条件に合わなかったので、申請はばつだった。
The application was rejected because it didn't meet the conditions.
ゲームで間違えたところに赤いばつ印を付けた。
I put a red X on the parts I got wrong in the game.
Slang for MDMA (ecstasy/molly), referring to the illegal psychoactive drug in colloquial usage.
クラブで誰かがばつを持ちかけてきたが断った。
Someone at the club offered me ecstasy, but I refused.
警察はばつの所持で数人を逮捕したと報道された。
Reports said the police arrested several people for possession of ecstasy.