Slovenly is what your great aunt Mehitabel might call you if you came to high tea without a necktie. It means "messy or unkempt," but is a word you probably won't hear messy or unkempt people using.
Slovenly has meant messy or unkempt since the 1500s, but it had a brief heyday before that of meaning "low or base." This class association remains embedded in the word — someone who uses the word slovenly today is most likely also going to raise his or her pinky while drinking from a cup of tea.