Sentence:  The day came indeed when her breathless auditors learnt from her in bewilderment that what ailed him was that he was, alas, simply not serious. Maisie wept on Mrs. Wix's bosom after hearing that Sir Claude was a <WSD>butterfly</WSD>nb.... 
Meaning of the word marked with <WSD> tags:  Someone seen as being unserious and (originally) dressed gaudily; someone flighty and unreliable. (from 17th c.)