From 'Token of Higher and Lower Culture' in Nietzsche's Human, All too Human

The free spirit a relative concept. A man is called a free spirit if he thinks otherwise than would be expected, based on his origin, environment, class, and position, or based on prevailing contemporary views. He is the exception: bound spirits are the rule; the latter reproach him that his free principles have their origin either in a need to be noticed, or else may even lead one to suspect him of free actions, that is, actions that are irreconcilable with bound morality. Sometimes it is also said that certain free principles derive from perverseness and eccentricity; but this is only the voice of malice, which does not, itself, believe what it says, but only wants to hurt: for the free spirit generally has proof of his greater kindness and sharp intellect written so legibly on his face that bound spirits understand it well enough. But the two other derivations of free-thinking are meant honestly; and many free spirits do indeed come into being in one or the other of these ways: But the tenets they arrive at thereby could still be more true and reliable than the tenets of bound spirits. In the knowledge of truth, what matters is having it, not what made one seek it, or how one found it. If the free spirits are right, the bound spirits are wrong, whether or not the former came to truth out of immorality and the others have kept clinging to untruth out of morality.
Incidentally, it is not part of the nature of the free spirit that his views are more correct, but rather that he has released himself from tradition, be it successfully or unsuccessfully. Usually, however, he has truth, or at least the spirit of the search for truth, on his side: he demands reasons, while others demand faith. (para.225)