Compound preposition

A preposition, only more tedious, and therefore beloved of our old friend the mediocre attorney.

We know that our legal brethren delight in perverting the ordinary use of words - nominalising verbs into nouns, and so on, and the compound preposition is a neat way of co-opting nouns, conjunctions — all kinds — into the servile business of putting one noun in relation to another.

Why, for example, exercise your rights under a contract when you can do so in accordance with or pursuant to it?