Mis- means bad or badly, wrong

misbehave (v) - to act out badly or in the wrong way

mischievous (adj) - tending to make minor bad choices; teasing; full of tricks; naughty

miserable (adj) - feeling badly; the condition of feeling unhappy

misfortune (n) - bad luck

misjudge (v) - to make a wrong or unfair decision about someone

mislead (v) - to guide someone into the wrong direction; to be a bad influence

misspell (v) - to spell a word the wrong way

mistake (n) - a bad or wrong decision; error

mistreat (v) - to treat someone badly

misunderstand (v) - to think the wrong thing about what was communicated