In English, adjectives (describing words) are usually placed before the noun (person, place or thing) they describe. In a few cases the adjective goes after the noun and is called a post-positive adjective. This causes problems.
One of the largest problems caused by post-positive adjectives is the confusion over plurals. Remember that the plural is formed with an S (or ES) added to the noun, not the adjective; so we have fathers in-law, not*father in-laws. Other examples of these plurals include: courts martial (military courts), Alcoholics Anonymous and cherries jubilee. (These terms are not all from Norman times, but the adjective order is.)
The possessive is also complicated and needs to be described without automatically adding an apostrophe S ( 'S ) to the end of the combined term. The form in the first set of sentences below is technically correct, but not used. The sentence is too confusing! It is not clear if the car belongs to the attorney general or is a general car belonging to an attorney. The second set of sentences, is clear and technically correct but not often used. The third set is not technically correct, but it is more commonly used. There is no clear solution.
This is the car belonging to the attorney general.
This is the uniform belonging to the postmaster general.
*This is the attorney general's car.
*This is the postmaster general's uniform.
* Error used as an example
It is simplest to use the standard position before the noun, but afterwards is not always wrong. (Although it sounds more pretentious.) This happens more often when describing the best or worst of something.
My parents want to send me to the best possible school.
My parents want to send me to the best school possible.
Using the adjective after the noun is appropriate for official government functions. So the meaning can vary for the same word depending on the position in which it is used.
She is looking for a responsible man who would be a good husband.
The police are looking for the man responsible for the crime.
He is a disinterested man who does not care about the problem.
He is a man disinterested in the problem and so is a neutral judge. (He has no money invested in the result of the problem.)
He lives in proper Hong Kong. That means everyone there behaves properly. (However unrealistic such a sentence may be...)
He lives in Hong Kong proper. That means HK island, not Kowloon or the New Territories.
Also adjectives ending with -able (or -ible) are sometimes used post-positively. However the standard order is still preferred, as it sounds normal.
Pink is the only available colour.
Pink is the only colour available.
Adjectives go after the noun if the noun is the direct object, when the adjective describes the resulting condition (caused by the verb, not the noun). These are not actually post-positive, but only look like it.
She makes him unhappy.
We painted the classroom green.
Remember that the plural is placed on the noun, no matter what the order. Post-positive terms must be explained to use the possessive, without simply adding 'S. While it is normal for the adjective to go before the noun in English, it is not always the case. So, be careful out there, but be tolerant of other's mistakes.