A place name ‘TOOTHILL’ - meaning ‘a lookout on a hill’ or ‘dweller by the lookout hill’

The old English spelling was TÖT-HYLL

From an Irish Surnames Register:

TUTTY  and/or TUTHILL

Tutty is included in the list prepared by the Registrar-General in 1891 as used synonymously with Tuthill.  Tuthill is an English toponymic, quite distinct from Tohill.  It first appears in Ireland in the army of the 1640s.  Families of the name acquired property in County Limerick and several other parts of the country under the land settlement of the Cromwellian and Restoration periods: they retained their place among the landed gentry during the following three centuries.  John Tuthill’s unedifying part (no other information) in the 1817 Limerick election is still remembered.

Irish and Anglo-Irish Histories.

Tuathal (Irish ‘ a man’s name; left handed’), King of Liffe, son of Ugaire: from which comes O’Tuathail, anglicised as O’Toole, Toole, Tootal, Tuohill, Tuthill, etc.  Died 956.  His grandson Tuathal was wounded at the battle of Clontarf and died in 1014, buried at Glendalough.   One derivation of the name is from the Irish ‘tuatha’ - territories, meaning one possessed of large landed property.

1185 Gilbert de Totehille - a Knight Templar - this is the name to which most UK searches for the origin of the name  point.