Hilary \hi-la-ry\ as a girl's name (also used as boy's name Hilary), is pronounced HILL-a-ree. It is of Latin origin, and the meaning of Hilary is "cheerful, happy". The name comes from the same root as "hilarious". Name of a fourth-century saint and a fifth-century pope. Hilaire (ee-LARE) is a French form. First Lady Hillary Clinton; actress Hilary Swank; singer Hilary Duff.