In the following sentence
The term Orwellian has evolved into a descriptive of totalitarian and authoritarian practices.
Is the word 'descriptive' a noun or an adjective? Now it is my understanding that practices is a noun and hence descriptive should be an adjective describing that noun but still, there is a bit of confusion especially when this sentence has been written in a different manner in some places like below.
Orwell’s work continues to influence popular and political culture, and the term Orwellian – descriptive of totalitarian or authoritarian social practices – has entered the language together with many of his neologisms, including Big Brother, Thought Police, Room 101, memory hole, newspeak, doublethink, proles, unperson, and thoughtcrime.