Judgment: Decision that something - usually an idea or statement - is true or false, or probable or improbable, or good or bad.
The reason to distinguish judgments is that there are - it seems - choices that something is true, probable or good, or any of its opposites, that differ from non-judgements that something is red, or sweet, or painful, that seem to be just given and unavoidable given one's sensations, and either need no judgement at all, or are judgments only in a weak and attenuated sense.
The reason there are judgments is precisely because what is judged is neither simple nor directly given or accessible in sensation, but requires comparison along several dimensions; weighing evidence; balancing desires, beliefs and knowledge; consulting diverse sources, both in oneself, in others and in books; and needs reference, for a sound decision (one that will probably turn out to have been correct later, and then often in the sense that one has not grievously erred through passion or prejudice), to what one has learned.
And indeed, skillful knowledge is recognized by sound judgment - decisions that such and such is true (or not), or a good option (or not), that later turn out to be mostly correct, and that either cannot be made at all by less skillful men, or are much less often correct when judged by less skillful men.
Also, it is noteworthy that much skilled judgment is required and involved in distinguishing one's own and each other's imaginations, fantasies and fictions, from real, possible or probable fact or desirable end.