Allister is an English spelling of Alistair, the anglicized Scottish Gaelic Alasdair, which is Alexander and means "defender of men". The double l makes it look like a surname, which suits the current fashion. Allister stood at number 4583 in 2000, climbed to its best rank of 2000 in 2021 and 2022 and sits at number 2995 in 2025.