There isn't a formal definition of success.

When we speak of ordinary unqualified knowledge, my thought is that we are implicitly relativizing to the standards imposed by our evolution-derived humanity. These are standards that determine when we consider it appropriate to store beliefs just as a human being, rather than in one's capacity as an expert of one or another sort. Such stored beliefs are to be available for later use in one's own thought or in testimony to others.

Success is better than failure; an attempt is a better attempt, it is better as an attempt, if competent than if incompetent; and it is better to succeed through competence - aptly - than through sheer luck.

Judgment is affirmation with the intention to thereby affirm competently enough, and indeed aptly. That distinguishes judgments from mere guesses.

If we have a better understanding of knowledge than we do of such justification or competence, then we can explain the latter through the former.

In my view there is a level of human knowledge that involves just getting it right aptly. This "animal" epistemic level is an inferior level in just the way of Diana's long shot in the dark while drunk. That shot is inferior in a certain respect if too poorly selected as a hunter's archery shot, even if not quite as poorly selected as would be a shot aimed at the moon. Even if Diana's too risky shot turns out to be apt by attaining success through sublime archery dexterity, it is still inferior in the particular respect of being so risky and hence so poorly selected.

In order to qualify as a judgment, an affirmation must aim at getting it right aptly, through competence, and not just through a lucky guess.