Lewis & Short

adversātīvus, a, um, adj. [adversor], adversative; in gram.: conjunctiones adversativae, which have an adversative signif. as opp. to each other, as tamen, quamquam, etsi, etiamsi, etc., Prisc. 1030 P.; while quamquam, etsi, etc., we now designate as concessive in relation to tamen.