Lewis & Short

illātīvus (inl-), a, um, adj. [infero], inferring, concluding, illative (cf. illatio, II. B.): particulae, Plin. ap. Diom. p. 410 P.
Subst.: illātīvum, an inference, conclusion: universale, particulare, Apul. Dogm. Plat. 3, p. 34, 24.