How do I define freethought?
To be a freethinker, one must be open to new ideas. Ideas that can be both exciting and terrifying, ideas that are unpleasant, unwanted, and downright ghastly to behold, albeit necessary. To be a freethinker is to accept that there is no black and white, nothing concrete, nothing to be broken down into this or that. Black and white are merely extremes of color; we do not live in a world that is black and white. Besides, reducing existence into such simplistic terms neglects the broad spectrum that we deal with every second of every day.
Freethought crushes dogma, undermines prejudice, vanquishes ignorance. There is no absolute to a freethinker. Any assertion is analyzed, interpreted, it's background checked, it's genesis traced, it's theory tested and, if found to be be true, accepted for what it is and no more. A lightning bolt is an atmospheric discharge of built up electricity, not a weapon thrown by a god, not an alien inspecting a new planet, not a direct consequence of global warming. Freethinkers do not assume the cheap and easy explanation for things.
Religion is an empire built by people who have had fear instilled upon them; the rulers live well, fed by the generosity exploited from below. Ignorance holds this institution together; dogma plays the role of sentinel. Religion opposes education and reason for the same reasons slave owners opposed education and healthcare for their "flock"; give the oppressed the instruments they need to break free, and they will. The religious fight science, reason, education, solely because they know that freethought will be the end of their reign.
The mind is the key. Control how people think, and you control how they behave. Religion has used this idea for millenia; I for one will say that much good has come from this. There has also been much evil. We no longer have any need or use for religion. There is so much more to be found in the world when you break yourself free of the mental restraints religion impresses upon us. Freethinking is freedom to see the world as it is; not as someone else tells you.