Hú Yīn 胡愔 (hào Jiànsù zǐ 見素子, “Master of Seeing the Simple”) was a mid-ninth-century female Daoist active at Tàibái shān 太白山 in Shǎnxī. Her sole surviving work is the short illustrated treatise Huángtíng nèijǐng wǔzàng liùfǔ bǔxiè tú 黃庭內景五臟六腑補瀉圖 KR5b0116 (DZ 432), which carries an authorial preface dated to the 848 wùchén year. The treatise — one of the most important Táng documents in Daoist medical-physiological theory — combines the visceral pantheon of the Huángtíng nèijǐng KR5b0015 with specific methods for restoring imbalance through qì-regulation and diet.
Hú Yīn is one of the small number of named women Daoist authors of the Táng. No CBDB record; beyond her signed work nothing biographical is preserved. Despeux, Immortelles de la Chine ancienne (1990), discusses her place within the broader Táng female Daoist fāngshù tradition.