Henshall identifies two theories about the origins of 奴 (DO, yatsu: slave, servant, guy), which contains 女 (woman) and 又 (hand).
One theory (which Henshall prefers) is that this 女 means “compliance,” whereas this 又 symbolizes “work.” If you work compliantly, you’re a slave or servant.
The other theory posits that 奴 actually refers to a female under someone’s “hand,” which is to say “under someone’s control” or “enslaved.”
Another dictionary proposes that 奴 initially referred to a woman forced to work and that the meaning later expanded to include both genders.