the word 'trustworthy' is a transparent compound formed from two old english elements. 'trust' originates from the old norse 'traust', meaning confidence or help, which itself is related to the proto-germanic traustą, implying firmness and security. the suffix '-worthy' derives from old english 'wurþig', meaning deserving or of value, connected to the concept of worth. the compound's logic is direct: describing someone who is 'deserving of trust' or 'worthy of confidence', evolving from the literal combination of these two concepts into a single adjective denoting reliability.

Structure: trust (confidence) + worthy (deserving) trust (from old english 'trēow', meaning faith, confidence; functions as the core noun/root). worthy (from old english 'wurþig', meaning deserving, suitable; functions as an adjective-forming suffix).