upstay means to sustain, support. Lexicurio rates it Sui generis — a strength score of 90 out of 100.
Etymology
From up- + stay.
verb
- To sustain, support.“those two villeins, which her steps vpstayd, / When her weake feete could scarcely her sustaine, / And fading vitall powers gan to fade, / Her forward still with torture did constraine […]”