ἐνθύμιον
From LSJ
ἐπ' αὐτὸν ἐπενθρῴσκει πυρὶ καὶ στεροπαῖς ὁ Διὸς γενέτας, δειναὶ δ' ἅμ᾽ ἕπονται κῆρες ἀναπλάκητοι → the son of Zeus is springing upon him with fiery lightning, and with him come the dread unerring Fates
English (Woodhouse)
scruple, point of conscience, qualm of conscience, something that weighs on one's conscience, twinge of conscience