mephitis
/məˈfaɪtɪs/
noun
- A very unpleasant, poisonous, or foul-smelling vapor or gas, especially from the ground.
- Ancient people believed that mephitis rising from the earth caused disease.
- The cave was dangerous because of the mephitis that could overcome anyone who entered.
- The miners wore masks to protect themselves from the mephitis in the deep tunnels.