Trustworthiness (Information System) definition in Computer Security terms:
Definition(s): The degree to which an information system (including the information technology components that are used to build the system) can be expected to preserve the confidentiality, integrity, and availability of the information being processed, stored, or transmitted by the system across the full range of threats. A trustworthy information system is a system that is believed to be capable of operating within defined levels of risk despite the environmental disruptions, human errors, structural failures, and purposeful attacks that are expected to occur in its environment of operation.
Source(s): NIST SP 800-53 Rev. 4
reference: CSRC Glossary