Duffy
An Irish surname from a Gaelic word meaning “dark” or “black.”
The #892 most common surname in the United States (2010 Census) — about 1 in every 7,950 Americans shares it.
Etymology
Duffy is an anglicized Irish surname, usually connected with Gaelic Ó Dubhthaigh or a closely related form. The core element is dubh, meaning “black” or “dark,” so the name was likely originally a nickname for someone with dark coloring or a dark-haired person. The sources also show alternative historical spellings and related forms such as O'Duffy and Dowey/Dooey, reflecting the many ways Irish names were rendered in English.
History
The name is long established in Ireland and appears frequently in Irish surname lists and county records. In 19th- and early-20th-century scholarship, Matheson ranks Duffy among common Irish surnames, and Woulfe treats it as a standard anglicized Irish family name. The surname spread widely through Irish emigration, especially to Britain, North America, and other English-speaking countries.
Origin
Regions
Variant spellings
Fun fact
The same Gaelic root dubh (“black”) lies behind a whole cluster of Irish surnames and anglicized forms, which is why older records can show several different spellings for what is essentially the same family name.
From the historical record
“[I r. and Gael. Mac Giolla Dhubhthaich — mac, son + giolla, gille, servant : v. Duffy] MAC KENDRICK, for Mac Hendrick (Celt. + Teut.) Son of Hendrick, q.v.”
— Surnames of the United Kingdom: a concise etymological dictionary (2 vols in 1)