The subjunctive mood (Greek ὑποτακτική (hupotaktikḗ) "for arranging underneath", from ὑποτάσσω (hupotássō) "I arrange beneath") along with the indicative, optative, and imperative, is one of the four moods of the Ancient Greek verb.
These can be: Such subordinate clauses are introduced by a conjunction or relative pronoun combined with the particle ἄν (án), e.g. ἐάν (eán) 'if', ὅταν (hótan) 'whenever', ὅσαν (hósan) 'whoever' etc.
For this area of meaning the imperfect and aorist indicative tenses are used in Ancient Greek.
The subjunctive can usually be recognised easily from the fact that it almost always has the letters ω (ō) or η (ē) in the ending, for example εἴπωμεν (eípōmen), γένηται (génētai).
The negative, as with almost all uses of the subjunctive, is μή (mḗ):[10] However, when the meaning of the negative command is "don't continue to do something", μή (mḗ) is used not with the subjunctive but with the present imperative:[12] The subjunctive mood is often used in indefinite subordinate clauses referring to an unknown time in the future (e.g. "if this should happen") or to an unspecified time in the present (e.g. "whenever this happens").
[15] Conditional sentences of this kind are referred to by Smyth as the "more vivid" future conditions:[16] The negative used with the potential subjunctive, as with the jussive subjunctive, is μή (mḗ): The same construction is used with πρὶν ἄν (prìn án) "before" and ἕως ἄν (héōs án) "until such time as" referring to an event or situation which it is expected will occur at an indefinite future time: Another very similar use of the subjunctive is in indefinite subordinate clauses following a conjunction such as ἐᾱ́ν (eā́n) "if ever", ὅταν (hótan) "whenever", ὃς ἄν (hòs án) "whoever", etc., referring to repeated actions in indefinite present time.
[29] On the other hand, when ὅπως (hópōs) is used, ἄν (án) is usually added, although ὅπως (hópōs) can also be used alone:[30] In a past context purpose clause, the optative mood without ἄν (án) is often used (see Optative (Ancient Greek)), but it is also possible to use the subjunctive even in a past context:[33] Purpose clauses can also be made with ὅπως (hópōs) and the imperfect, aorist, or future indicative.
[41] Similar to its use with verbs of fearing, the subjunctive with μή (mḗ) is sometimes used in doubtful assertions, meaning "it may be the case that" or (with μὴ οὐ(κ) (mḕ ou(k))) "it may not be the case that", especially in Plato:[42] A similar construction, but with οὐ μή (ou mḗ) rather than μὴ οὐ (mḕ ou), can also be used for an emphatic assertion, as in this sentence from the New Testament, always negative and usually with the aorist subjunctive:[44] The subjunctive, like the imperative, is found in only three tenses: the present, aorist, and perfect.