noun
registration block; blacklisting
Internet domain: blocking registration of domain names, email addresses, or accounts, often to prevent spam or abuse.
迷惑メール対策として、特定のドメインを登録禁止にした。
As a countermeasure against spam, we blocked registration from specific domains.
noun
registration ban (soccer)
Sports domain: a ban on registering new players, typically imposed on a club as a penalty.
そのクラブは財政違反で選手の登録禁止処分を受けた。
The club received a player registration ban due to financial violations.
Compound of 登録 (registration) and 禁止 (prohibition).