The name Seamus is a boy's name of Irish origin meaning "supplanter". Seamus is ranked #977 on our popularity charts and is often added to lists like Irish Boy Names - Baby Names and discussed in our forums with posts like "Quick Question Thread?!".
From the experts:
Parents who have tired of Sean are now contemplating Seamus, the Irish form of James, which has a lot more substance and verve.
One of the name's most famous bearers is the 1995 Nobel Prize-winning Irish poet Seamus Heaney. Seamus is also a Harry Potter name—Seamus Finnigan is a half-blood wizard friend of Harry's.
At a time when the police force was predominantly Irish, "shamus" became a slang term for a detective.