I usually think of judgment as a process of interpretation or a related kind of wisdom, but at least since early modern reformulations of Aristotelian logic, “a” judgment has also traditionally meant a logical proposition, or an assertion of a proposition.
An older, but still post-Aristotelian notion is that what the early moderns called a judgment “A is B” should be understood (on the model of its surface grammar) as the potentially arbitrary predication “A is B”. Such a potentially arbitrary predication by itself does not contain enough information for us to assess whether it is good or bad. The predication model was associated with a non-Aristotelian notion of truth as simple correspondence to supposed fact.
L. M. De Rijk, arguably the 20th century’s leading scholar on medieval Latin logic, developed a very detailed textual argument that the understanding of logical “judgments” in such grammatical terms is actually an unhistorical misreading of Aristotle. In the first volume of his Aristotle: Semantics and Ontology, De Rijk concluded that Aristotle’s own logical or semantic use of “is” or “is not” should be understood not in the traditionally accepted way as a “copula” or binary operator of predication, but rather as a unary operator of assertion on a compound expression — i.e., on the pair (A, B), as opposed to its two elements A and B.
I also want to emphasize that Aristotle himself did not admit simple, potentially arbitrary predications as “judgments”. The special form of Aristotelian propositions makes them express not arbitrary atomic claims as is the case with propositions in the standard modern sense, but two specific ways of compounding subclaims. Aristotle’s two truth-value-forming operations of combination and separation (expressed by “is” and “is not”) limit the scope of what qualifies as a proper Aristotelian “judgment” to cases that are effectively equivalent to what Brandom would call judgments of material consequence or material incompatibility (see Aristotelian Propositions). What the moderns would call Aristotelian “judgments” thus end up more specifically reflecting judgments of what Brandom would call goodness of material inference.
Proper Aristotelian “judgments” thus turn out to express not just arbitrary predications constructed without regard to meaning, but particular kinds of compound claims that can in principle be rationally evaluated for material well-formedness as compound thoughts, based on the actual content of the claims being compounded. (Non-compound claims are just claims, and do not have enough content to be subject to such intrinsic rational evaluation, but as soon as there is some compounding, internal criteria for well-formedness come into play.)
So, fortuitously, modern use of the term “judgment” for these ends up having more substance than it would for arbitrary predications. For Aristotle, truth and falsity only apply to what are actually compound thoughts, because truth and falsity express assessments of material well-formedness, and only compound thoughts can be assessed for such well-formedness. The case for the fundamental role of concerns of normativity rather than simple surface-level predication in Aristotelian truth-valued propositions is further supported by the ways Aristotle uses “said of” relations.
Independent of this sort of better reading of Aristotle, Brandom in the first of his 2007 Woodbridge lectures points out that Kant also strongly rejected the traditional analysis of judgment in terms of predication. Brandom goes on to argue that for Kant, “what makes an act or episode a judging in the first place is just its being subject to the normative demand that it be integrated” [emphasis in original] into a unity of apperception. This holistic, integrative view of Kantian judgment seems to me to be strongly supported by Kant’s discussion of unities of apperception in the second edition of the Critique of Pure Reason, as well as by the broad thrust of the Critique of Judgment.
Thus, a Kantian judgment also has more substance than the standard logical notion, but while an Aristotelian “judgment” gets its substantive, rational character from intra-propositional structure, a Kantian judgment gets it from inter-propositional structure.