Possible meanings are 1) this is a euphemism. AT: "has sexual relations with" or 2) it simply means "to marry." (See: [[rc://en/ta/man/translate/figs-euphemism]])
This means a man cannot have sexual intercourse with his sister, even if she has a different mother or father. The full meaning of this statement can be made explicit. AT: "whether it is his full sister or half-sister" (See: [[rc://en/ta/man/translate/figs-explicit]])
This phrase means the man is responsibile for his sin. AT: "He is responsible for his sin" or "You must punish him" (See: [[rc://en/ta/man/translate/figs-idiom]])