娟 is a bound morpheme, never used alone. Common compounds: 娟秀 (juānxiù, elegant and delicate), 婵娟 (chánjuān, the beautiful moon / a beautiful woman). Also extremely popular as a component of women's names.
culture
婵娟 appears in Su Shi's famous Mid-Autumn Festival poem: 但愿人长久，千里共婵娟 ('May we live long and share the beauty of the moon across a thousand miles'). One of the most quoted lines in Chinese poetry.
女 marks 娟 as a feminine-quality word, used overwhelmingly to describe women — "graceful, lovely." Common in female given names (婷娟, 美娟). Same family: 婷, 娴, 婉 — all femininity-flavoured adjectives.
phonetic
肙yuān
small worm (phonetic stem)
肙 supplies the sound yuān → juān. You also see this phonetic in 涓 juān (trickle), 捐 juān (donate), 鹃 juān (cuckoo). All share the j-/y- drift and the -uān rhyme. No standalone reading you'd use today.
