OT: It's a reasonable question, BalanchineFan, and you'd be correct if a) we were speaking in purely descriptive terms, since the word is frequently used in the second meaning of if 2) Homans (and Kirkland) were writing in Middle English, since the word did originally mean "generous" or "abundant," as in a "fulsome harvest." However, today the first usage remains the "correct" one for careful writers. IMO it's a useful word to have around for the first meaning and not terribly necessary for the second.
The American Heritage Dictionary is particularly helpful in these matters because of their "Usage Notes." It outlines the issue well, I think. The Cambridge Dictionary takes a firmer line. You will note that the American Heritage usage note suggests, sadly/wisely, that the word be omitted where it may cause ambiguity.
I think in a book of this quality it's a mistake (describing Betty Cage as having a "fulsome body"). There are many other adjectives you could use that aren't going to distract your reader (or maybe you could just not even refer to Cage's curves at all (?)).