-Someone who does things that are not acceptable in society so they keep it hidden .hidden dark secrets about you know one knows or very few people know about you because its shameful.
Someone who hides bad habits about themselves or lifestyle.
He used to be a closetdweller til he decided to let it be know public he is gay,
That guy is such a closetdweller, he is gay but tries to hide it out of shame.
what a closetdweller , she drinks and gets drunk by her self everyday after work and she thinks no one knows,
I am a closetdweller, I smoke only when no one or my close friends are with me cause I dont want a bunch of people to know.