Sentence:  I take a whiff of the most sincerely <WSD>sinful</WSD> cookies in the history of the world. It's a recipe I saw in "People" magazine once at the dentist's office, and Dr. Segal would not approve of its ingredients (or maybe she would, in the interest of keeping her business afloat). 
Meaning of the word marked with <WSD> tags:  decadent (luxuriously self-indulgent)