μεσοποτάμιος
From LSJ
τὸ γὰρ εὖ πράττειν παρὰ τὴν ἀξίαν ἀφορμὴ τοῦ κακῶς φρονεῖν τοῖς ἀνοήτοις γίγνεται → undeserved success engenders folly in unbalanced minds
English (LSJ)
[ᾰ], α, ον,
A between rivers, αἱ μ. (sc. χῶραι) Str.15.1.18; ἥδε ἡ μ. ib.30: esp. as pr. n. Μεσοποτᾰμία (sc. χώρα), ἡ, Mesopotamia, Plb.5.44.6, Str.11.12.2, etc.:—hence Μεσοποτᾰμίτης [ῑ], ου, ὁ, Luc.Hist.Conscr.24. II in the middle of the river, ἐν μ. νήσῳ Plu.Oth.4.