φρενοβλαβής
From LSJ
ἔνδον σκάπτε, ἔνδον ἡ πηγή τοῦ ἀγαθοῦ καί ἀεί ἀναβλύειν δυναμένη, ἐάν ἀεί σκάπτῃς → Dig within. Within is the wellspring of Good; and it is always ready to bubble up, if you just dig. | Look within. Within is the fountain of the good, and it will ever bubble up, if thou wilt ever dig.
English (LSJ)
ές, (βλάπτω)
A deranged, crazy, Hdt.2.120, Eup.181.7, Luc.Syr.D.43, Hierocl.in CA 24p.472M., etc.