The definite article before certain adjectives

Question

There are some adjectives that require only the definite article: wrong, perfect, right, etc. So, for example:

That's the wrong answer.

The Bentley is the perfect car for commuting.

He made the right choice.

So replacing all the the's with a's will be ungrammatical. However, in these examples the indefinite article would sound more logical, as the listener doesn't know what particular choice/car/answer the speaker's talking about. So, the question is: 1)What's the rule applied here? 2) Can you list other adjectives that require the definite article irrespectively?

Answer 1

My answer is semantic, not grammatical. The issue is one of meaning, not of rules of syntax.

If you intend that there is one unique correct answer then "the right answer" is the correct meaning since the noun "answer" is fully determined by the adjective "right".

Similarly, there are usually many incorrect answers: so "That's a wrong answer" is correct and meaningful. You are wrong to say that this is not grammatical. Similarly, you can use "the perfect car" to imply that the car is fully determined by its perfection, but you can also use "a perfect car" to imply that there are others that are equally good.

So in all the examples you give, both "a" and "the" are grammatically possible. A native speaker would intuitively choose an article according to the meaning that they want to give.

Generally, adjectives that are incomparable will be more determining. If you can't be "righter" or "less right", then a noun will be fully determined by the adjective and so the article chosen will be "the".

Answer 2

If you can form a subsentence like "the car is perfect", then it's "the perfect car".

"A car is perfect" is close to saying "car is perfect", which sounds wrong. Better would be "any car is perfect" or "cars are perfect" to make the difference.

"An answer is wrong" without context doesn't sound wrong, could mean "one answer" or "any answer". It actually doesn't matter that there could be different wrong answers. Conceptually, wrong answers are all the same, even added up together they won't make a correct answer. Therefore it would be correct to say "That is the wrong answer". Of course, "That is the right answer" does seem to imply there was only one. But strictly speaking, if there were different answers, any answer not highlighting all perspectives would be incomplete and thus not a [edit: the] right answer at all. At least that seems to be in line with the stackoverflow culture on answering.

I am not sure on this either, as my writing shows, so I'd like to know any better answers.