Where does “aislúbtha” come from?

aislúbtha (Irish) comes from Irish ais-, from Irish áis, from Old Irish ais, from Proto-Celtic *axsi-, from Proto-Celtic *axsilā, from Proto-Indo-European h₂eḱs-, from Proto-Indo-European h₂eǵ- — to drive.

aislúbtha (Irish): retroflex

Definitions

retroflex

Ancestry of “aislúbtha”, step by step

Step	Language	Word	Meaning
1	Irish	ais-	re-, back
2	Irish	áis	convenience
3	Old Irish	ais	back
4	Proto-Celtic	*axsi-	—
5	Proto-Celtic	*axsilā	—
6	Proto-Indo-European	h₂eḱs-	axis, axle
7	Proto-Indo-European	h₂eǵ-	to drive

Every word from Proto-Indo-European h₂eǵ- →Every word from Proto-Indo-European h₂eḱs- →Every word from Irish ais- →