Pope John Paul did an amazing job in his encyclical at articulating what freedom is. Here is a glimpse of it:
Fides et Ratio
In that act, the intellect and the will display their spiritual nature, enabling the subject to act in a way which realizes personal freedom to the full.(15) It is not just that freedom is part of the act of faith: it is absolutely required. Indeed, it is faith that allows individuals to give consummate expression to their own freedom. Put differently, freedom is not realized in decisions made against God. For how could it be an exercise of true freedom to refuse to be open to the very reality which enables our self-realization? Men and women can accomplish no more important act in their lives than the act of faith; it is here that freedom reaches the certainty of truth and chooses to live in that truth.