Could you please tell me the meaning of "hollowly" in the following excerpts from the chapter Four and Six of The Great Gatsby by F. Scott Fitzgerald? Does it mean "faintly", "with a cavernous voice", or "with a false ring"
a) I took him into the pantry where he looked a little reproachfully at the Finn. Together we scrutinized the twelve lemon cakes from the delicatessen shop.
“Will they do?” I asked.
“Of course, of course! They’re fine!” and he added hollowly, “...old sport.”
b) A massive and lethargic woman, who had been urging Daisy to play golf with her at the local club tomorrow, spoke in Miss Baedeker’s defence:
“Oh, she’s all right now. When she’s had five or six cocktails she always starts screaming like that. I tell her she ought to leave it alone.”
“I do leave it alone,” affirmed the accused hollowly.
The word "hollowly" in both instances you cite is used not for its meaning but for its sound. It is used like onomatopoeia. The sound of the word represents the sounds of the voices of Gatsby and of Miss Baedeker when they make the statements you quote. It is a matter of tone rather than of literal meaning.
Try saying the word "hollow" with the emphasis on the two vowels. Your voice should sound hollow because of the word. Now try repeating Gatsby's "old sport" with the same tone as you had to use when saying "hollow." Notice that "old sport" also has two "o" vowels. It is only because of the vowels that Fitzgerald could describe the utterance as hollow. If, for instance, Gatsby had said something like, "my friend," Fitzgerald could not have characterized it as "hollowly."
Fitzgerald, through Nick, wanted the reader to "hear" the tone and then infer from the tone what the speaker was feeling. The hollow tone of "old sport" suggests that Gatsby is feeling rather hopelessly frightened, though he is pretending to be enjoying the occasion. This is understandable because he instigated it and has to act self-confident even though he is a bundle of nerves.
Try saying "hollow" again and then repeating Miss Baedecker's words, "I do leave it alone," using the same tone. Notice again that there are two vowels in her statement that could give a hollowness to the tone. These are the "ooh" in "do" and the "oh" in "alone." Here again, the right vowels have to be present to be described as hollow. If Miss Baedecker had said something like, "I am a light drinker," it couldn't be described as "hollowly" because the necessary vowels wouldn't be there. Evidently the vowel that is necessary for hollowness is "o."
To use an analogy, some writers like to use the words "he hissed" or "she hissed." For example: "Stop speaking to me!" she hissed. She can hiss because of the "s" sounds in "stop" and "speaking." But if the author wrote something like, "Get out! Go away!" she hissed, it would be wrong because there is no "s" for the lady to hiss. Weak writers make such mistakes frequently. Fitzgerald was a genius and a conscientious writer; he would never make such a mistake.