Shamus Is A Boy’s Name Of Irish Origin. Derived From The English Name James, This Rather Traditional Name Has The Unique Meaning Of “supplanter.” Other Spellings Of This Name Might Be More Familiar To You, Such As Seamus Or Séamas, But This Phonetic Spelling Will Keep People From Mispronouncing Baby’s Name. This Name Is The Perfect Choice For The Little One Who Has Supplanted All Others In Your Heart.