Sentence:  “Wilbert Cream is a ... what's the word?” I referred to the letter. “A kleptomaniac ... Does any thought occur to you?” “It most certainly does. I am thinking of your uncle's collection of old silver.” “Me, too.” “It presents a grave temptation to the unhappy young man.” “I don't know that I'd call him unhappy. He probably thoroughly enjoys <WSD>lifting</WSD> the stuff.” 
Meaning of the word marked with <WSD> tags:  To steal.