Where does “Jalaja” come from?

Jalaja (English) comes from Sanskrit जल, from Sanskrit जल् — to be sharp; to be stiff or dull.

Ancestry of “Jalaja”, step by step

Step	Language	Word	Meaning
1	Sanskrit	जल	stupid, unintelligent, dumb; a stupid man, idiot;...
2	Sanskrit	जल्	to be sharp; to be stiff or dull

Jalaja — Etymology, Origin & Word History | Etymology Explorer