o·mer·ta 
(ō-mûrtə, ō′mĕr-tä)
(ō-mûrtə, ō′mĕr-tä)n.
A rule or code that prohibits speaking or divulging information about certain activities, especially the activities of a criminal organization.
[Italian omertà, probably from alteration (influenced by Sicilian omu, man) of Spanish hombredad, manliness, from Spanish hombre, man; see OMBRE.]