動詞の形N4
〜な（禁止）
Don't do...! (prohibition)
Structure
V-辞書形 + な
Explanation
The dictionary form of a verb + な expresses prohibition, equivalent to a stronger, imperative-style 〜てはいけない. It is blunt and used by male superiors with subordinates, or on warning signs and public notices.
Examples
ここでタバコを吸うな。
Don't smoke here.
授業中にスマートフォンを使うな。
Don't use your smartphone during class.
Note
〜な is stronger and blunter than 〜てはいけない. In speech, 〜ないで is more common. Posted notices often use 〜な.