Sentence:  “Your theory is <WSD>bulldust</WSD>, Arthur,” said Pancho. “Nothing but <WSD>bulldust</WSD>. You should play your best doubles players even if they are playing singles. If they are fit, they are not going to be too tired. McEnroe would not have lost that match.” 
Meaning of the word marked with <WSD> tags:  Nonsense; blatantly false statements.