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"forbid" is also used as a crossword clue. If that's what you saw, the answer is often ban (3 letters).
Definitions
Prohibit or command that something must not be done.
Used in a sentence
“Smoking in the restaurant is forbidden.”
“[…] the Mole recollected that animal-etiquette forbade any sort of comment on the sudden disappearance of one's friends at any moment, for any reason or no reason whatever.”
“Solon also forbade the export of corn and other agricultural products, with the single exception of olive oil, of which Athens had a surplus.”
Source: Wiktionary, CC BY-SA 4.0
Used as a crossword answer1 curated clues
01“Refuse to allow”6 letters
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