Where does “lúb” come from?

lúb (Old Irish) comes from Old Norse hlaup, from Old Norse hlaupa, from Proto-Germanic hlaupaną, from Proto-Indo-European klaup-.

Ancestry of “lúb”, step by step

Step	Language	Word	Meaning
1	Old Norse	hlaup	leap, jump; a run", "literally," "a leap
2	Old Norse	hlaupa	to leap, jump, spring
3	Proto-Germanic	hlaupaną	to jump forward, to leap
4	Proto-Indo-European	klaup-	—

lúb — Etymology, Origin & Word History | Etymology Explorer