Hi- My grandfather was Dr. Henry Claris Sweany, born in Idaho. His father was Col. Andrew Sweany of Missouri via Indiana, who fought on the Union side during the Civil war and afterwards moved to Idaho to escape the James Gang, who killed another member of the family, a train conductor named Westfall. My grandfather eventually moved back to Missouri,and other family members landed in Canada, among them George Sweany, who became a celebrated WW2 war hero.
Some family members have done quite a bit of history, and found that Sweany originates from Sweeny or Sweeney. They were a warrior clan of Scots Vikings, originally the clan of Mac Suibhne (Mac Sweeny,)under the Chief of Argyle, of Scotland. They evetually migrated and settled around 1588 to support their Irish kin in the northern area around Donnegal, Ireland and some later moved to County Cork. There are several castles in Ireland of this clan- (Sweeney,) Rahan Castle in Banagh, Doe Castle in Fanad, and Dungloe Castle, first clan settlement in Ireland in 1588. Most of they are now ruins.
Castle Sween is in Argyll, Scotland, which is the oldest stonebuilt castle in Scotland- 12th century, which has been restored.
The Sweeney (clan Suibhne) crest shows Three Boars and a creature that appears to be a weasel or otter (hard to tell,) inside a shield with an armored headpiece at the top amongst vines. It has been described as a clan of the battle axe- (no comment on that one!) This was a warrior clan that fought as mercenaries for other clans.
There is a Sweeney clan web page where you can find more history.