A broad concept applied to a person who has the hobbyist spirit to tinker.
This is a large topic which I have plenty of notes on which will eventually find themselves here.
There's a difference between "knowing how to program" and "being a programmer" just like there's a difference between being literate and being a writer.
"Becoming a hacker" is an unreasonable goal, but understanding how great programmers think and learning their habits can help one on one's own journey. At the very least, it's important to learn from the mistakes of others.