Lewis & Short

magnĭdĭcus, a, um, adj. [magnusdico], that talks big, boastful, bragging (ante- and post-class.): homo, Plaut. Mil. 3, 3, 48: Persae, Amm. 23, 6, 80.
Transf., of abstr. things: mendacia, Plaut. Rud. 2, 6, 31.