Where does “fostaid” come from?

fostaid (Middle Irish) comes from Old Irish ·asstai, from Old Irish ad·suidi — stop, detain; stops, holds back, detains,...

Ancestry of “fostaid”, step by step

Step	Language	Word	Meaning
1	Old Irish	·asstai	—
2	Old Irish	ad·suidi	stop, detain; stops, holds back, detains,...

fostaid — Etymology, Origin & Word History | Etymology Explorer