A word denoting an action (walk), occurrence (happen), or state of being (be). It is a central part of speech because we structure sentences around it.

For an overview of the different parts of speech, have a look here.

In Greek Verbs are denoted by their:
– Person: first (the speaker), second (the person addressed), third (the person, animal or thing spoken about)
– Number: singular or plural, shows the singularity or plurality of the subject of the verb
– Tense: when does the action take place (present, past, future) and whether it is complete or ongoing
Voice: active or passive
– Mood: indicative, subjunctive, imperative shows whether the action is something real or definitive, wanted or expected or an order given.

A site that has 1000 verbs with their conjugations:

Home of Greek Verbs