Gress?

This is a close relative of the last post, but it's one root that spawns all sorts of words. The root itself, however, didn't quite make it into the English language.

You can regress. You can digress. You can progress. You can even aggress. So if there is any justice in the lexical world, you should be able to gress. But according to Merriam-Webster, I gress not.

The root is in the Latin gradir, which means to go or to step. It's where we get the word grade. So why can't you get gressing instead of getting going? Why can't you gress in something instead of stepping in it? It just wasn't meant to be.

So the root of aggressive turned out to be passive? Typical.