In English I guess we have understand and withstand. And used to have words like counterstand and overstand. While thinking about this I had a curious thought

In English I guess we have understand and withstand. And used to have words like counterstand and overstand. While thinking about this I had a curious thought that maybe the word "against" derives not just from "agegn" but from a two word phrase "agegn standan". Google is not helpful. Claude AI suggests that the "st" ending actually developed later, likely through analogy with other prepositions ending in "-st" like "amongst" and "whilst."