Connelly comes from an Irish surname derived from O Conghaile, often linked to valor or fierce spirit.
Connelly is an Anglicization of the Irish surname Ó Conaill, meaning "descendant of Conall" — and Conall itself is one of the great old Gaelic names, combining cú (hound, warrior) with gal (valor, prowess), so that its deepest meaning is something like "strong wolf" or "valiant warrior." The O'Connell and Connelly/Connolly families were powerful presences in medieval Ireland, spread across Connacht and Munster, their name appearing in annals and poetry as emblems of leadership and martial spirit. The name has been worn by figures of real consequence.
Daniel O'Connell (1775–1847), "The Liberator," fought for Catholic emancipation and Irish rights with an oratorical brilliance that made him a hero across Europe. James Connolly (1868–1916) was a socialist revolutionary and one of the leaders of the Easter Rising; his execution by British forces made him a martyr of Irish independence. In the arts, Jennifer Connelly brought the name to Hollywood glamour, winning an Academy Award for A Beautiful Mind (2001).
The Scottish comedian Billy Connolly gave it a ribald, irreverent energy. As a given name rather than a surname, Connelly is newer territory — part of the broader shift toward using family names as first names that has accelerated since the 1990s. It suits both boys and girls, though in practice it skews male when used as a first name.
Its three rhythmic syllables — con-NEL-ly — have a natural confidence to them. For families with Irish roots, Connelly as a given name is a way of carrying ancestry forward without the formality of a traditional Gaelic choice.