Wisdom from the Early Stoics, Zeno of Citium 39

A predicate is, according to the followers of Apollodorus, what is said of something; in other words, a thing associated with one or more subjects; or, again, it may be defined as a defective expression which has to be joined on to a nominative case in order to yield a judgement.

Of predicates some are adjectival, as e.g. "to sail through rocks." 

Again, some predicates are direct, some reversed, some neither. 

Now direct predicates are those that are constructed with one of the oblique cases, as "hears," "sees," "converses"; while reversed are those constructed with the passive voice, as "I am heard," "I am seen."

Neutral are such as correspond to neither of these, as "thinks," "walks." 

Reflexive predicates are those among the passive, which, although in form passive, are yet active operations, as "he gets his hair cut": for here the agent includes himself in the sphere of his action. 

The oblique cases are genitive, dative, and accusative.

—Diogenes Laërtius, 7.64-65