Sentence:  Professionally a lawyer , that is to say associated with dignity , reserve , discipline , with much that <WSD>is</WSD> essentially middle-class , he is compelled by an impossible love to exhibit himself dressed up , disguised - that is , paradoxically , revealed - as a child , and , worse , as a whore masquerading as a child . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)