A function of the intellect; that act by which we predicate one thing of another.
Saint Thomas has defined it as the act by which the mind combines or separates two terms by affirmation or denial.
A judgment always implies the presence of two ideas in the mind, a comparison of these two ideas, and the affirmation of their agreement or disagreement.
It is expressed verbally by the proposition, such as, "Snow is white."
Judgment is the chief act toward which all thought converges, since it alone is true or false.
The most important division of judgments is that which distinguishes analytical and synthetical judgments.
According to the conception of the Scholastics, if the predicate may be inferred from the consideration of the subject, because it is already contained in its nature or essential relations, the judgment is analytical, or necessary, e.g., "The whole is greater than any of its parts."
If the predicate adds something to the subject which cannot be stated previously to the experience of it, something which no mere analysis of the subject would reveal, the judgment is synthetical or contingent, e.g., "This book has 600 pages."
New Catholic Dictionary