In a harsh, discordant, or unpleasant-sounding manner; with sounds that clash and grate.
From 'cacophonous' + the adverbial suffix '-ly'; 'cacophonous' itself uses the '-ous' suffix (full of) added to 'cacophony'.
This word demonstrates English suffix stacking: 'kakos' (Greek) + 'phone' (Greek) + '-ous' (Latin-derived) + '-ly' (Germanic)—proving that modern English is a genuine hybrid that mashes together roots from all its historical influences.
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