unavailable; disabled; cannot be used
Used for functions, features, or items that are not available or have been disabled, often in software, services, or formal notices.
This feature is currently unavailable.
The account was suspended and the service became disabled.
Similar meaning, but 利用不可 often emphasizes that something cannot be utilized or accessed, while 使用不可 focuses on the inability to use or operate it.
Compound of 使用 (use) + 不可 (impossible, not allowed).