My guess is that it is not.
The surname Maguire/McGuire is Mag Uidhir in Irish (Gaelic). It is the genitive form of Odhar(dun-coloured).
Keith Maguire has written: 'The rise of modern Taiwan' -- subject(s): Politics and government, Social conditions, Economic conditions, Foreign relations
Robert Maguire has written: 'Modern churches of the world' -- subject(s): Church architecture, Church buildings 'Case of primary cancer of the femur' -- subject(s): Cancer, Femur
It would be spelled the same, Donna.
In a more modern Irish Gaelic Maol Íosa [mael eesa], 'devotee of Jesus'.A Scottish Gaelic version is Maoilios.
"Mac Toirdhealbhaigh" is the Irish Gaelic form.In a more modern spelling Mac Toiríolaigh.
Modern Irish and Scottish Gaelic would not spell a word that way: perhaps you mean "dearcadh"? Or Old Irish?
In modern times, 'Celtic' people are Irish, Scottish highlanders, Manx, Welsh, Bretons and Cornish. Those are the only regions where Celtic languages are still spoken.
In the 10th century, the language spoken in the Scottish Highlands was Early Gaelic, a precursor to modern Scottish Gaelic. This language was brought to Scotland by Gaelic-speaking peoples from Ireland and became the dominant language in the region during this time.
Modern Irish - tine; Old Irish - teine Scottish Gaelic - teine Manx - aile The name Áed is another word for 'fire'. Delbaeth means 'fire shape'.
The Irish language 'equivalent' of the Scottish Ian could be either Seán or Eoin, (forms of John). The original Scottish Gaelic spelling of Ian is Iain, incidentally.
In Scottish Gaelic it means "my brown-haired daughter" or "my brown-haired girl". In this case it most probably means "my brown-haired girl", since this is the title of a Gaelic love song. By the way in modern Gaelic grammar it should be "mo nighean dhonn", because nighean (girl) is feminine.
The Gaelic or Irish language dates back as far as 500 AD. This means the language was first written over 1500 years ago. Gaelic has evolved into modern day Irish and is spoken by a 80% of Ireland.