dismal (adj) depressing; causing gloom or misery; causing bad feelings
malady (n) bad health; illness; sickness
malaria (n) bad air; a disease usually spread by infected mosquitoes
malefactor (n) an evildoer; a person who does bad things
malevolent (adj) a word that describes a person or character who wishes bad things would happen to others
malfeasance (n) wrongdoing or bad conduct by a public official
malice (n) mischief; evil intent; bad will
malignant (adj) harmful; something bad enough that it could result in death when related to cancer
malnourished (adj) having bad health or having poor nutrition
malodorous (adj) bad smell; stinky