noun
Used for official or explicit bans, often in signs, rules, or formal contexts. Frequently appears in compounds like 禁煙 (no smoking) or 禁止 (prohibition).
ここは写真撮影が禁です。
Photography is prohibited here.
禁を破ると罰せられる。
If you break the ban, you will be punished.
禁止 is the more common and general word for prohibition. 禁 is often used in compounds or as a concise, formal term.
The kanji 禁 has long been used to express prohibition or restriction. The reading きん is the standard on'yomi.