Where does “caifeacht” come from?

caifeacht (Irish) comes from Irish -acht, from Old Irish -acht, from Proto-Celtic -axtā, from Proto-Celtic axtā.

Ancestry of “caifeacht”, step by step

StepLanguageWordMeaning
1Irish-achtNominal suffix, used to form abstract ideas or...
2Old Irish-acht-ness, -hood; forms abstract nouns
3Proto-Celtic-axtā—
4Proto-Celticaxtā—
Every word from Proto-Celtic axtā →Every word from Irish -acht →Every word from Old Irish -acht →