The name Rooney is a girl's name meaning "descendent of the champion". Rooney and is often added to lists like Celebrity-Inspired Baby Names and discussed in our forums with posts like "Boys Makeover- Two Middles".
From the experts:
Talented actress Rooney Mara (originally born Patricia Rooney) has single-handedly transformed this Gaelic surname into a wearable and elegant girls' name. Often said to mean "red-haired", the original surname, rendered as O' Ruanaidh, actually means "descendent of the champion". Trivia note: the most famous Rooney, Mickey Rooney, was originally born Joseph Yule.