The imperfect in Greek refers to the imperfect tense. The imperfect tense is roughly equivalent to the English progressive tense. Study chapter 21 in BBG or this.
present – I walk; imperfect – I was walking
It is past time, internal aspect. Imperfects always take an augment but never a tense formative.
| Person | Active Voice | Middle Voice | Passive Voice |
|---|---|---|---|
| 1st Singular | ἔλυον | ἐλυόμην | ἐλυόμην |
| 2nd Singular | ἔλυες | ἐλύου | ἐλύου |
| 3rd Singular | ἔλυε(ν) | ἐλύετο | ἐλύετο |
| 1st Plural | ἐλύομεν | ἐλυόμεθα | ἐλυόμεθα |
| 2nd Plural | ἐλύετε | ἐλύεσθε | ἐλύεσθε |
| 3rd Plural | ἔλυον | ἐλύοντο | ἐλύοντο |