This perfectly valid English word does appear, as per the rules, in the Chambers 21st Century English Dictionary, and does not fall foul of any other requirements. It seems unfortunate that a newspaper, of all things, would be afraid of a "rude" word.
Since "u" was the key letter in that Target, the answers could even have included "c*nt", and everyone would have understood sufficiently what was meant. If the Dominion Post is too prudish even for that, then perhaps it simply shouldn't run puzzles that contain answers which offend its sensibilities. Pretending that part of our language simply doesn't exist seems the worst option all round.
I look forward to you courageously publishing the related noun "labia" in tomorrow's Target solutions.