“Freethinking” may be popular, but it’s an oxymoron as so-called freethinkers exclude things they won’t talk about or consider (god). Many free-thinkers are the most closed-minded people we’ve ever met — freethinking being an oxymoron as a mind works like a parachute, it only functions when open.
A person who forms opinions about religion on the basis of reason, independently of tradition, authority, or established belief. Freethinkers include atheists, agnostics and rationalists.
No one can be a freethinker who demands conformity to a bible, creed, or messiah. To the freethinker, revelation and faith are invalid, and orthodoxy is no guarantee of truth.
That obviously causes a logical problem, and becomes an oxymoron; you can’t think freely if you’re excluding areas of consideration. So let’s try something else:
A person who forms opinions on the basis of reason, independent of authority or tradition, esp. a person whose religious opinions differ from established belief.
The phrase “differ from established belief” still excludes areas of exploration, so thus can’t be truly freethinking; let’s use the following definition for freethinker, which passes logical muster:
A freethinker forms opinions on the basis of reason and logic.
If we use that definition, most sane people will agree thinking for yourself is a good thing; don’t get sucked in by group-think (notice atheists can’t be free-thinkers as atheists abandon critical thinking to hold logically absurd beliefs, and place limits on what they’ll consider).