Diminutive of Gertrude, from Germanic elements meaning 'spear of strength.'
Trudy is a diminutive that began its life as a pet form of Gertrude, the venerable Germanic name composed of ger, meaning spear, and þruð, meaning strength — making its full-length ancestor something close to "spear of strength" or "strong spear." Saint Gertrude of Nivelles, a 7th-century Belgian abbess who became the patron saint of travelers, gardeners, and the recently deceased, carried the name into Catholic Europe, and Gertrude of Helfta, the 13th-century mystic, gave it further spiritual prestige. Trudy inherited all of this history while wearing it lightly, the nickname stripping away the formality and keeping the warmth.
In the early-to-mid 20th century, Trudy stood on its own as a given name in American and British records, part of a cohort of sunny nickname-names that included Judy, Patty, and Sandy. It was a name that projected cheerful capability — not glamour, but the dependable warmth of a person who shows up and gets things done. Gertrude Stein, one of the 20th century's most formidable literary and intellectual presences, bore the full form and gave it a modernist cachet, but most Trudys of that era happily ignored the high-art connection.
Trudy faded from popular use in the 1970s and 1980s as parents moved toward more formal names, but it has recently attracted renewed attention as part of the broader revival of vintage mid-century names. It is compact, unambiguous, and impossible to misspell — practical virtues that feel refreshing. It shares the retro-chic appeal of Judy and Betty while remaining rarer, and it carries a fundamental optimism in its sound that is difficult to engineer and easy to fall in love with.