sa.ni describes the wife set in contrast to the loved wife in the firstborn-son scenario.

The attested use describes a wife contrasted with a loved wife in the setting where each bears sons and the firstborn belongs to the former.

1. The wife contrasted with the loved wife · dominant

   In Deuteronomy 21:15, the feminine singular absolute form identifies one of two wives in contrast to the loved wife; the APB renders the paired description as “the one loved and the one hated” and again distinguishes “the loved and the hated” when both bear sons.

   Deuteronomy 21:15

In the Anselm Project Bible: In Deuteronomy 21:15, the APB presents the contrast with “the one hated” and later “the hated.” These renderings show the verse's contrast rather than a precise lexical mapping.