sulphurous UK /sʌlˈfjuɹəs/US /ˈsʌlfəɹəs/ adjective2 •Containing sulfur.The miners slowly walked up the steep crater walls, stopping frequently while clouds of sulfurous gas blanketed the crater in the background. — 2015 •Of, or relating to sulfur, especially in its lower oxidation state. formsmore sulphurous · most sulphurous