Lewis & Short

ālūcĭnor (better than all- or hall-; cf. Gron. ad Gell. 16, 12, 3), ātus, 1, v. dep. [prob. from ἀλύω, ἀλύσσω; ἄλη, ἀλύκη; cf. Gell. 16, 12, 3], to wander in mind, to talk idly, prate, dream (syn.: aberro, deliro, desipio, insanio): alucinari: aberrare et non consistere, atque dissolvi et obstupefieri atque tardari, Non. 121, 20 (apparently not used before the time of Cic., yet cf. alucinatio): quae Epicurus oscitans alucinatus est, Cic. N. D. 1, 26, 72: suspicor hunc alucinari, id. Att. 15, 29; Gell. 16, 12, 3: indicium vagi animi et alucinantis, id. 4, 20, 8: epistolae nostrae debent interdum alucinari, to follow no definite train of thought, to digress freely, Cic. Q. Fr. 2, 9: alucinans pastor, Col. 7, 3, 26.