Cathasach

• Origin: Irish-Gaelic
• Meaning: “vigilant.”
• Gender: Masculine
• Pronunciation: KATH-e-Sakh

The name is derived from the Gaelic word for “vigilant,” and was a relatively common name in Medieval Ireland. It was borne by a 7th-century Irish king of Ulster. It is sometimes spelled as Cathassach. Today it is very rare but its legacy has been left behind in the surname of Casey (meaning descendant of Cathesach), which is also sometimes used as a unisex given-name in the English-speaking world, though it is not recommended.

Sources

• https://en.wikipedia.org/wiki/Cathassach_mac_Lurgain
• https://www.behindthename.com/name/cathasach
• https://celt.ucc.ie/index.html