悦耳
yuè ěr · HSK 7
sweet-sounding
👂🎵 悦 pleasant + 耳 ear = pleasant to the ear, sweet-sounding
耳 is the ear radical (note the two strokes like an ear outline). Pair it with 悦 happy/pleasing and you get a sound that pleases the ear. Same 悦 as in 喜悦 joy.