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wrong; bad; improper; unjustifiable; inadvisable
not allowed; not possible
failing grade
ここでの撮影は不可です。
Photography is not allowed here.
法律により未成年者の入場は不可ですよ。
Minors are not allowed to enter.
予算不足で彼の計画は実行不可だった。
His plan was impossible to execute.