directly opposed Antonyms

two-fold selfsame returnable resembling resemblant reciprocal paired modular mated kindred interconvertible interchangeable synonymic synonymous twain suchlike substitutable look-alike pen pal blood relative blood relation autologous nucleoside undifferentiated two-sided two identical identic complementary commutable collateral collatable coincidental cognate coetaneous carbon bifold biconjugate agnate congeneric congenerous connate idem homologue homologous dyadic duple dualistic ditto coupled