Where does “-óir” come from?

-óir (Old Irish) comes from Proto-Brythonic -ọr, from Latin -ārius, from Proto-Italic *-āzios.

Ancestry of “-óir”, step by step

Step	Language	Word	Meaning
1	Proto-Brythonic	-ọr	—
2	Latin	-ārius	—
3	Proto-Italic	*-āzios	—

-óir — Etymology, Origin & Word History | Etymology Explorer