The Spanish pudrir, “to rot,” has a surprising connection to the English, foul, a word meaning the same but sadly very underused these days — although still when quoting Macbeth: fair is foul and foul is fair!
Both come from the same Indo-European root *pu, meaning, “to rot.”
But the English one sounds so different because, in the Germanic branch of Indo-European, the p- sound turned into the f- sound. But now in the Latin branch.
Thus the initial f+vowel of foul maps to the initial f+vowel of pudrir.
From the same root are more fun words including defile, putrid, and pus. What wonderful imagery!