Homer, Od. 8.176-177
“Thus, you have a conspicuous appearance, but no god
could make you different: your mind is useless.”
ὡς καὶ σοὶ εἶδος μὲν ἀριπρεπές, οὐδέ κεν ἄλλως
οὐδὲ θεὸς τεύξειε, νόον δ’ ἀποφώλιός ἐσσι
Schol. ad Od. 8.177.12-14
“Apopholios properly means someone who is not worthy to be numbered among men as a complete person, one who is lacking the use of words or deeds for the proper occasions. They also call schools phôleoi. Therefore, someone who has not gone to school is called useless, i.e. unschooled”
καὶ ἔστι κυρίως ἀποφώλιος ὁ μὴ ἄξιος συναριθμεῖσθαι ἀνδρῶν ὁλότητι ἐν φωτὶ, ἤγουν ἐν καιρῷ ἔργων ἢ λόγων δεομένῳ. φωλεοὺς λέγουσι τὰ παιδευτήρια. ὁ γοῦν μὴ φοιτῶν εἰς τὰ παιδευτήρια λέγεται ἀποφώλιος. E.
Schol. ad. Od. 5.182
“Apophôlia: uneducated things. For phôleoi are schools. Or, they are things which someone shouldn’t declare because they are ineloquent or lack understanding”
ἀποφώλια] ἀπαίδευτα. φωλεοὶ γὰρ τὰ παιδευτήρια. ἢ ἃ οὐκ ἄν τις ἀποφήναιτο ὡς ἄρρητα ἢ ἀσύνετα. P.V.
“Apophôlios: empty, unesteemed, simple. Or, uneducated.”
†ἀποφώλιος· μάταιος. ἀδόκιμος, εὐτελής. ἢ ἀπαίδευτος (θ 177) p
….“this comes from phôleon: for schools are called phôleoi because people linger and spend time in them. Therefore they call uneducated people apophôlioi.”
γέγονε δὲ παρὰ τὸν φωλεόν· φωλεοὶ γὰρ λέγονται τὰ παιδευτήρια παρὰ τὸ ἐν αὐτοῖς φωλεύειν καὶ διατρίβειν. τοὺς οὖν ἀδιδάκτους ἀποφωλίους ἐκάλουν.
φωλεύεω, “to lurk in a hole or a den”….“to lie hidden”
More Etymologies: Notes (from Perseus)
 ἀποφώλιος. The derivation of this word is most uncertain; it is commonly compounded of “ἀπὸ-ὄφελος” [from ophellos, “use”], while others refer it to a root “φα”, ‘to blow,’ or to “ἀπάφεσθαι”, ‘to cheat.’ Autenrieth proposes to refer the latter part of the word to the same root as “φύω” and “φώς”, so as to mean, ‘grown out of shape.’