We literally don’t know the oldest word(s) for “bear”
as a result of this sort of practice.
bear means “the brown one”. The common explanation is that bears were either objects of cultic veneration or seen as kinda human or some combination thereof, so their true name was hidden — as a measure of respect or fear or honor. or some combination of the three.
Allusive and indirect names then got applied to “bear” too — a common scholarly opinion is that “Beowulf” is “Bee-hunter”, a bear. (Though opinions differ there).