おんおんMeanings1adverb taking the 'to' particle, adverbbawling; crying loudlyrare termonomatopoeic or mimetic wordRare onomatopoeic adverb describing loud, unrestrained crying, often with 泣く. Typically used with と.赤あかん坊ぼうがおんおん泣ないている。The baby is bawling loudly.