What an interesting question!
First, it depends how big the crocodile is; second, it depends on what species the crocodilian is.
If it's a small alligator, threatening the eyes usually works (going...
Crocodile comes from the Greek words krokos and deilos, meaning "pebble worm". It probably refers to the elongated, "worm" like body of the animal and its pebbly looking skin.