Clancy registers 62 times at rank 1643 on male pets. It's an Irish surname that became a given name, warm and slightly roguish, with a built-in storytelling quality. A dog named Clancy sounds like a character who would have at least one legend told about him at the dog park.
The Irish Surname-as-Name Tradition
Clancy derives from the Irish Mac Fhlannchaidh and has been used as both surname and given name in Irish-American communities for generations. It belongs with Riley, Brady, and Finnegan in a cohort of Irish-origin names warmly adopted as pet names. The name has a slightly boisterous, good-natured energy that's easy to feel even if it's hard to place.
Sound and Breed Fit
CLAN-see is two syllables with a strong first beat and a breezy finish. The name calls well and has enough personality to carry across a crowded park. It suits medium to large male dogs with sociable, confident personalities. Irish Terriers are the heritage match, but any outgoing, friendly breed carries the name naturally. The human name is at /names/clancy.
The Counter-Reading
Clancy's roguish charm implies a dog who might steal a sandwich but will look so remorseful about it that you can't stay angry. For owners who want that energy in a name, Clancy delivers. For owners who want something more dignified, it's probably the wrong register.