εἴπερ

A. if really, if indeed, Il. 3.25, etc.; esp. even if, even though, Il. 7.117, Od. 1.167, etc.; εἴ. καί 9.35; εἴ. τε Il. 10.225; εἴ. γε A. Ch. 198, Pl. Prt. 312a, etc.; εἴ. γε δή Id. Tht. 182c; with words between, εἴ. γάρ τε χόλον γε . . Il. 1.81; εἴπερ ἔσται γε A. Ag. 1249, cf. Pl. Plt. 275e; καλῶς, εἴπερ ποτέ, ἔχει Th. 4.20; εἴπερ ἄρα Jul. Or. 7.216b.

II. in Att. and Trag. to imply that the supposition agrees with the fact, if as is the fact, since, Th. 6.14, etc.; but with impf. it implies that it is contrary to the fact, εἴπερ ἦν πέλας if I had been (but I was not), S. El. 312, cf. 604; also εἴ. ἐκτελεῖς ἅπερ λέγεις if only you will keep your word, Id. Ichn. 48.

III. with an ellipse, if you must, Ar. Nu. 227; ἀλλ’ εἴ. but if so, Pl. Prm. 150b, Arist. EN 1101a12; cf. εἰ B. VII.