Greek verbs are simultaneously incredibly complicated and remarkably simple, as many verbs follow common ending patterns, or inflections, but there are vast number of these endings. Unlike English verbs, which normally have at most five forms (sing, sang, sung, singing, sings), a single Greek verb can have hundreds of forms. However, by breaking Greek verbs down into their respective components, each verb can quickly and easily be identified. This means every verb can give out a lot of useful information about the rest of the sentence. For instance, the English verb form are singing could take a variety of subjects (you are singing, you all are singing, we are singing, they are singing), but a Greek verb includes the subject within its ending.
Principal Parts
A verb in Greek has any of 6 principal parts. A principal part is a form of a verb that cannot be derived from another form—that is to say, they are principal, fundamental to the verb. Tenses are formed by adding inflectional affixes to an appropriate stem, given by a principal part. The 6 principal parts are:
- Present and imperfect, active and middle
- Future, active and middle
- Aorist, active and middle
- Perfect and pluperfect, active
- Perfect and pluperfect, middle
- Future and aorist, passive
It is important to stress that not all verbs have all 6 principal parts. For example, ἥκειν, meaning "to have arrived", has only one principal part—the first, ἥκω; while grammatically present (that is to say, it has a present stem and uses present and imperfect endings), it has a perfect sense. The Greek copula has two principal parts, the first and second, being εἰμί and ἔσομαι. In view of these limitations, it is not possible to form a pluperfect tense for either of these two verbs. On the other hand, οἶδα, has a sole fourth principal part. It has a perfect stem and uses perfect and pluperfect endings. Its grammatical meaning is "to have seen", but the implication is therefore "to know", and it is used in the latter sense.
Personal Endings
The most important marker on a verb (and usually the easiest to spot) is its personal ending. A finite verb will alter its ending depending upon its subject's person (first, second, or third person) and number (singular or plural). This is similar to the way verbs are formed in English: for example, if you take almost any verb in the present tense in the third person singular (the he/she/it form) will add an -s to the end: I work, but she works. Here is how the present of a simple verb conjugates, or changes its personal ending:
Present Tense
| Singular | 1 | λύω | I release |
| 2 | λύεις | You release | |
| 3 | λύει | He/she/it releases | |
| Plural | 1 | λύομεν | We release |
| 2 | λύετε | You release | |
| 3 | λύουσι(ν) | They release |
A simple mnemonic (with a twist) for the plural is "Men eat sushi".
Notice that the stem, λυ-, does not change. Additionally, the ν at the end of the third person plural form is usually inserted at the end of a sentence and also before another word that begins with a vowel. This ν makes the ending of a Greek form easier to distinguish, so that words do not elide (this added ν is known as the ν-movable in some grammars). If the verb is not at end of a sentence or before a word that begins with a vowel, the ending is just -ουσι.
Tenses
Verbs also change according to their time frame. Since most narrative occurs in the past, these verb forms are critical to know. There is a slightly different set of endings used by verbs in the past, and, in Classical Greek, the past time frame is denoted by adding a past temporal augment, commonly as an ἐ-, to the beginning of the verb.
Imperfect Tense
| Singular | 1 | ἔλυον | I was releasing |
| 2 | ἔλυες | You were releasing | |
| 3 | ἔλυε(ν) | He/she/it was releasing | |
| Plural | 1 | ἐλύομεν | We were releasing |
| 2 | ἐλύετε | You were releasing | |
| 3 | ἔλυον | They were releasing |
This is known as the imperfect form. Again, notice how it is composed of the same stem as in the present (λυ-), but includes a past temporal augment. Note also that the accent moves back one syllable.
Future Tense
The future tense takes the same endings as the present tense. However, it is different from a present verb by the addition a sigma to the present stem, then adding the present endings as normal:
| Singular | 1 | λύσω | I shall release |
| 2 | λύσεις | You will release | |
| 3 | λύσει | He/she/it will release | |
| Plural | 1 | λύσομεν | We shall release |
| 2 | λύσετε | You will release | |
| 3 | λύσουσι(ν) | They will release |
Aorist Tense
The aorist tense expresses an action in a non-continuous aspect and generally in the past. The aorist tenses are formed from the third principal part. Morphographically, there are three types of aorist stems that are regular: first (or sigmatic) aorist, second aorist, and root aorist. First aorist stems are quite common, second aorists less so, and root aorists limited to a few verbs. A verb usually has only one of the three types of aorists. These are the first aorist forms of λύω:
| Singular | 1 | ἔλυσα | I released |
| 2 | ἔλυσας | You released | |
| 3 | ἔλυσε(ν) | He/she/it released | |
| Plural | 1 | ἐλύσαμεν | We released |
| 2 | ἐλύσατε | You released | |
| 3 | ἔλυσαν | They released |
Here are the second aorist forms of λείπω (to leave):
| Singular | 1 | ἔλιπον | I left |
| 2 | ἔλιπες | You left | |
| 3 | ἔλιπεν | He/she/it left | |
| Plural | 1 | ἐλίπομεν | We left |
| 2 | ἐλίπετε | You left | |
| 3 | ἔλιπον | They left |
Here are the root aorist forms of δύω:
| Singular | 1 | ἔδυν | I caused to sink |
| 2 | ἔδυς | You caused to sink | |
| 3 | ἔδυ | He/she/it caused to sink | |
| Plural | 1 | ἔδυμεν | We caused to sink |
| 2 | ἔδυτε | You caused to sink | |
| 3 | ἔδυσαν | They caused to sink |
Irregular verbs
Like most languages, Ancient Greek has irregular verbs, which cannot be conjugated on the basis of principal parts alone. There are a number of irregular verbs that appear often in Ancient Greek texts, and they must be known along with the regular verbs. Here follows the present tense of the verb to be:
| Singular | 1 | εἰμί | I am |
| 2 | εἶ | You are | |
| 3 | ἐστί | He/she/it is | |
| Plural | 1 | ἐσμέν | We are |
| 2 | ἐστέ | You are | |
| 3 | εἰσίν | They are |
As you can see, like Ancient Greek, even the English forms of to be are far from predictable!
Deponent verbs
Some verbs have middle or passive endings but are active in meaning. Consider βούλομαι (to want):
| Singular | 1 | βούλομαι | I want |
| 2 | βούλει | You want | |
| 3 | βούλεται | He/she/it wants | |
| Plural | 1 | βουλόμεθα | We want |
| 2 | βούλεσθε | You want | |
| 3 | βούλονται | They want |