going public; becoming public knowledge
Used when a private matter becomes known to the public or is brought into the open, often with a nuance of scandal or unwanted exposure.
If this matter becomes public, the company's credibility will be lost.
彼は家族の内輪もめを表沙汰にしたくなかった。
He didn't want to make the family feud public.
taking to court; recourse to litigation
Specifically refers to bringing a dispute into the legal system, making it a public court case.
示談がまとまらず、ついに表沙汰になった。
The settlement talks broke down, and it finally went to court.