Cease and desist

Etymology

A legal doublet pairing "cease" (from Latin "cessare," to stop) with "desist" (from Latin "desistere," to leave off). English law is full of such twinned synonyms — one from Latin, one from French — a habit dating to the era when documents hedged by using both tongues, and the redundancy became formal ritual.

noun phrase · /seess and dih-ZIST/
A formal demand that someone stop an allegedly unlawful activity and not resume it.
What it names
The opening move of many legal disputes — a warning shot on paper — that often settles matters before any lawsuit.
Example
The band sent a cease and desist over the sampled riff, and the ad was pulled within a week.
Related idea
A cease and desist is a private demand from one party; an injunction is a court order carrying the force of law, so ignoring the letter is risky but ignoring the injunction is contempt.