dank unpleasant; dark unpleasantly moist From the context, I understood that the night is unpleasant to some extent. It is a “tropical night,” which explains why it is moist or humid.
palpable intensely felt evident; readily seen Because the night is described as a “dank, palpable night that presses its warm blanket against the yacht,” I thought palpable meant “hot,” but when I checked the dictionary definition, I realized it could contextually mean “intensely felt.”
doggedly determinedly with persistence Because I read that “Rainsford swam doggedly,” I realized he did it with determination.
ardent enthusiastic passionate When I read that Zaroff’s father was an ardent sportsman, I realized that it meant he was enthusiastic.
scruples principles morals, principles Zaroff says that Rainsford’s scruples are ill-founded when he calls Zaroff a murderer, which is why I thought that scruples meant principles.
ennui feeling tired boredom When Zaroff gets bored of hunting, he says he is afflicted by ennui. So I figured this word meant being tired of or bored of something.
zealous passionate extremely passionate or enthusiastic When I read that Zaroff is a zealous hunter, I guessed that the word meant passionate because so much of the story is about his love of hunting.
uncanny strange mysterious The general could follow Rainsford’s trail even at night, which made me think uncanny meant “strange” or “supernatural.”
mocking making fun of ridiculing; contemptuous The trap Rainsford sets for the general is not successful, which makes the general mock him, so I assumed it meant “to make fun of.”
placid relaxed calm; pleasant Since placid was used to describe a pastime, I assumed it meant “relaxed and easygoing.”