Sense

1. throwing in covertly, by way of caution or reproof, by way of interruption
2. askance

Examples

• τοῖα δ’ ὑποβλήδην λευκώλενοσ ἔννεπεν Ἥρη· (Colluthus, Rape of Helen, book 175)
• τότε δὴ κρατὺσ Ἀργειφόντησ χῶρον ὑποβλήδην ἐσκέψατο, πῦρ ἀμαρύσσων, ἐγκρύψαι μεμαώσ· (Anonymous, Homeric Hymns, 46:5)
• ἀτὰρ μετὰ τήνγε παρασχεδὸν αὖτισ ἀνῶρτο Ὑψιπύλη, καὶ τοῖον ὑποβλήδην ἔποσ ηὔδα· (Apollodorus, Argonautica, book 1 13:4)
• καὶ δή μιν ὑποβλήδην προσέειπεν· (Apollodorus, Argonautica, book 3 7:26)
• τὴν δ’ ὅγε δῆθεν ὑποβλήδην προσέειπεν· (Apollodorus, Argonautica, book 3 19:2)

Source: Henry George Liddell. Robert Scott. "A Greek-English Lexicon". revised and augmented throughout by. Sir Henry Stuart Jones.