To forbid, disallow, or proscribe officially; to make illegal or illicit.
"The new law prohibits smoking in all indoor public spaces."
In plain English: To prohibit something means to officially say that it is not allowed and must be stopped from happening.
"The school rules prohibit students from bringing mobile phones to class."
Usage: Use prohibit when an authority makes something strictly forbidden by law or rule, often requiring the structure "prohibit someone from doing something." Avoid confusing it with synonyms like ban if you need to emphasize official legal power rather than general disapproval.
The word comes from the Latin prohibeo, which originally meant "to fence off" or "prevent." It entered English through Middle English as a term for stopping someone from doing something.