Other forms: prohibited, prohibiting, prohibits
To prohibit something is to forbid it officially, by rule or by law. Not discouraged — not allowed.
It is the formal word, and it belongs on signs and in regulations, where smoking is prohibited and unauthorised access is prohibited. Ban is the everyday equivalent. It takes from and a verb ending in -ing, so prohibiting somebody from entering. The noun prohibition means the act of forbidding, and with a capital letter it names the American ban on alcohol between 1920 and 1933.
1verbprohibitTo forbid something officially.
“The rules prohibit any form of advertising.”
Also accepted in games: ban
Proto-Indo-European
*per-
Latin
prohibeō — to fend off, prevent, prohibit
Middle English
prohibiten
English, today
prohibit
From Middle English prohibiten, from Latin prohibeō (“to fend off, prevent, prohibit”) (through past participle prohibitus).
Etymology from Wiktionary, CC BY-SA