The origin of this word is loosely within contexts of a general expansion in the english language by grammar nazi's trying to perfect the abstraction of an unusable word.
It has no exact definition because it means every single possible word, idea, location, person, action, emotion, adjective and any other thing you can think of at once. To use the word prophecate anywhere in any sentence is to say everyword and idea at the same time. It is by definition the infinity of words.
The prophecators prophecated prophecatingly at the nearest prophecation office, they did so without prophecation. (each occurence of the word prophecate in this sentence is a different word in and of itself.)