Sentence:  [The butler] joined us with a telegram for Bobbie on a salver. From her mother, I presumed, calling me some name which she had forgotten to insert in previous communications. Or, of course, possibly expressing once more her conviction that I was a guffin, which, I thought, having had time to ponder over it, would be something in the nature of a bohunkus or a <WSD>hammerhead</WSD>. 
Meaning of the word marked with <WSD> tags:  A stupid person, a dunce.