There are several synonyms for the word "more stenchful" that can be used to describe an unpleasant, foul odor. One option is "more malodorous," which implies an offensive smell that is stronger and more unpleasant than usual. Another alternative is "more pungent," which suggests a sharp and intense odor that can be overpowering and lingering. Additionally, "more fetid" is a term often used to describe a strong and unpleasant smell, particularly when referring to something rotten or decaying. Other synonyms for "more stenchful" include "more noxious," "more rank," "more nauseating," and "more putrid".