μηδείς
Etym. i. e. μηδὲ εἷς, μηδὲ μία, μηδὲ ἕν
I. "and not one", related to οὐδείς as μή to οὐ, Il., etc.; —rare in Pl., Xen.
2. μηδὲ εἷς, which (so written) is never elided even in attic, retained the first emphatic sense "not even one", and often had a Particle between, as μηδ᾽ ἂν εἷς, or a prep., μηδ᾽ ἐξ ἑνός, μηδὲ περὶ ἑνός etc., Plat.
II. "nobody, naught, good for naught", ὁ μηδείς Soph.; pl., οὐ γὰρ ἠξίου τοὺς μηδένας id=Soph.:— so, μηδέν or τὸ μηδέν often as Subst., "naught, nothing", id=Soph.; μηδὲν λέγειν to say "what is naught", Xen.; τοῦ μηδενὸς ἄξιος Hdt.; ἐς τὸ μηδὲν ἥκειν Eur.;—and of persons, τὸ μηδέν "a good for naught", τὸ μηδὲν εἶναι of an eunuch, Hdt.; τὸ μ. ὄντας Soph.
III. neut. μηδέν as adv. "not at all, by no means", Aesch., etc.