Sentence:  Although Miss Pross, through her long association with a French family, might have known as much of their language as of her own, if she had had a mind, she had no mind in that direction ... So her manner of marketing was to <WSD>plump</WSD> a noun-substantive at the head of a shopkeeper without any introduction in the nature of an article ... 
Meaning of the word marked with <WSD> tags:  To cast or let drop all at once, suddenly and heavily.