Where does “underliggen” come from?

underliggen (Middle English) comes from Old English underliċġan — to underlie, to be subject to, give way to.

Ancestry of “underliggen”, step by step

Step	Language	Word	Meaning
1	Old English	underliċġan	to underlie, to be subject to, give way to

underliggen — Etymology, Origin & Word History | Etymology Explorer