Lewis Short
mastrūca | mastrūga (noun F) : (), , Sardinian; v.infra
* A garment made of skins, a sheepskin, a skin: mastrucam, quod Sardum est, inridens Cicero ex industria dixit,Quint. 1, 5, 8: mastruca vestis Sardonica ex pelliculis ferarum, de qua Cicero pro Scauro: Quem purpura regalis non commovit, eum Sardorum mastruca mutavit?Isid. Orig. 19, 23, 5 (Orell. Cic. Fragm. Scaur. § 45, d, p. 268); so Prud. Symm. 2, 695.— As a term of abuse,a sheepskin, a ninny,Plaut. Poen. 5, 5, 34.
Charlton T. Lewis, Charles Short, A Latin Dictionary