Closet Smoker

Someone who smokes (nicotine mainly but it could really be anything)but not to the knowledge of others (partners, family members or friends.) Someone who keeps it very much in the dark and are usually obsessively defensive about the fact that they do indeed smoke. They often deny it while contradicting themselves with passing comments, behavioral pattern's and mannerism that resemble a smoker.

Surrounded by smokers, her eyes gleamed like a closet smoker} who craved a cigarette.