Lewis & Short

prīvātīvus, a, um, adj. [privo], denoting privation; in gram., privative, negative (post-class. for privans): ne particula privativa est, Gell. 13, 22; cf.: pars, quam Graeci κατὰ στέρησιν dicunt, id. 5, 12, 10.
Hence, adv.: prīvātīvē, negatively, Boëth. Analyt. Prior. 1, p. 483.