The predicate is what is affirmed or denied of the subject. In “Zayd is present,” the predicate is “present,” because presence is affirmed of Zayd.
In “Zayd is not present,” the relevant predicate is still presence, but its connection to Zayd is denied. Do not confuse the predicate with the affirmative or negative character of the judgment.
“The student is diligent” — predicate: diligent.
“This water is not warm” — predicate: warm, which is denied.
A predicate may express a quality, species, genus or another predicable concept.