bareos

βαρέως [1 verse] (adv) "Dull" is from bareos, which as an adverb means "impatiently," "slowly," "with dignity," "(of hearing) with disgust," "heavily," "pressed down," "with difficulty," and "weighed down;" as an adjective, not the form here, it means "heavy in weight," "heavy with age," "infirmity or suffering," "heavy to bear," "grievous," "burdensome," "grievous," "oppressive," causing disgust," "indigestible," "violent," "weighty," "grave," "ample," "of persons," "severe," "stern," "wearisome," "troublesome," "overbearing," "important," "powerful," "difficult," of soldiers "heavy-armed," of sound, "strong, deep, bass," of musical pitch, "low," of speech, "unaccented," and of smell, "strong, offensive." - "Dull" is from an adjective/adverb which means generally as an adjective "heavy (in many forms)" and, as an adverb "heavily," but with many, many specific uses. Here it is in the form of a adverb and has a specific meaning of "with disgust" when applied to listening.