A sōphrōnis a person aware of his limitations in a positive as well as a negative sense: he knows what his abilities and nature do and do not permit him to do. He is a self-controlled man in the sense that he will never want to do what he knows he cannot or should not. Aristotle differentiates him from the enkratēs, a man who also knows what his abilities and nature permit and do not permit, but who, though feeling drawn to what he cannot or should not do, has the moral fiber to resist temptations and follow the voice of reason instead. (His opposite, the akratēs, or ‘morally weak man,’ succumbs to temptation.) These terms refer not only to different virtues, but also to essentially different types of personality. A sōphrōnis well-balanced through and through; he gives the impression of self-control without effort or strain. The enkratēs, on the other hand, has an intense and passionate nature which he is, indeed, strong enough to control, but not without a struggle. He is ‘morally strong’ in his victory; the sōphrōn, on the other hand, is not even tempted. (313-4)
Aristotle. Nicomachean Ethics. Trans. Martin Ostwald. Prentice Hall, 1999.