Verb to be (εἰμί)
| Sg. | Pl. | Sg. | Pl. | Sg. | Pl. | ||||
| Indicative | Present | Future | Imperfect | ||||||
| 1 | εἰμί | ἐσμέν | ἔσομαι | ἐσόμεθα | ἤμην | ἦμεν | |||
| 2 | εἶ | ἐστέ | ἔσῃ | ἔσεσθε | ἦς | ἦτε | |||
| 3 | ἐστί(ν) | εἰσί(ν) | ἔσται | ἔσονται | ἦν | ἦσαν | |||
| Infinitive | εἶναι | ἔσεσθαι | - | ||||||
| Imperative | |||||||||
| 2 | ἴσθι | ἔστέ | - | - | - | - | |||
| 3 | ἔστω | ἔστωσαν | - | - | - | - | |||
| Subjunctive | |||||||||
| 1 | ὦ | ὦμεν | - | - | - | - | |||
| 2 | ᾖς | ἦτε | - | - | - | - | |||
| 3 | ᾖ | ὦσι | - | - | - | - | |||
| Optative | |||||||||
| 1 | εἴην | εἶμεν | - | - | - | - | |||
| 2 | εἴης | εἶτε | - | - | - | - | |||
| 3 | εἴη | εἶεν | - | - | - | - | |||
| Participle | (present) | ||||||||
| Sg. | Pl. | ||||||||
| N | G | D | A | N | G | D | A | ||
| masc | ὤν | ὄντος | ὄντι | ὄντα | ὄντες | ὄντων | οὖσι(ν) | ὄντας | |
| neut | ὄν | ὄντος | ὄντι | ὄν | ὄντα | ὄντων | οὖσι(ν) | ὄντα | |
| fem | οὖσα | οὔσης | οὔσῃ | οὖσαν | οὖσαι | οὐσῶν | οὔσαις | οὔσας | |