Lewis & Short

pŭsillĭtas, ātis, f. [pusillus], littleness, smallness (post-class.), Tert. adv. Herm. 14: intellegentiae, Lact. Opif. D. 1: animi, id. ib. 6, 17, 17: meae pusillitatis auctoritas, Hier. Ep. 152.