concubine, deprecatory self-reference for women

妾 is composed of 辛 (bitter) and 女 (woman). 辛 is a pictograph of a chisel-like sharp tool, which can be understood as an instrument of punishment. Thus, 妾 depicts a woman subjected to physical punishment, originally meaning a female slave. Later, it extended to refer to a man’s concubine and was used as a humble self-reference by women in ancient times.