Attributive - The adjective appears before the noun it describes.
I have a fluffy cat named Alfie.
I drive a grey car.
Predicative - The adjective follows a verb.
Alfie is white.
The car is grey.
Postpositive - The adjective appears directly after the word it relates to.
I wish I had cats aplenty to play with.
I used to work in accounts payable.
More about Postpositive adjectives
Postpositive adjectives are not as common in English as they are in other languages like French and Spanish. It's also important to not confuse ANY adjective that immediately follows a noun as a postpositive adjective. Of course this would only be an important distinction if one were teaching grammar.
"They bought a van big enough to fit both our families." The word 'big' is not a postpositive adjective, but rather a predicative adjective. The sentence is really 2 clauses that omitted the words "that is". It really reads like this:
"They bought a van that is big enough to fit both our families"
Another important thing to remember is that in English, adjectives are never pluralized.
Singular - Director general
Plural - Directors general
Postpositive adjectives are also often found with superlatives
Worst conditions possible
best room available
List of some more popular postpositive adjectives
Battle Royale (book)
Can you think of any others?