slim waist; beautiful waistline
Describes a slender, attractive waist, often in the context of physical appearance or fashion.
She exercises every day to maintain her slim waist.
That dress is designed to emphasize a beautiful waistline.
Compound of 美 (び, 'beauty') and 腰 (こし, 'waist'). The reading びこし follows standard on'yomi for 美 and kun'yomi for 腰.