When used as a verb, the word “presage” means to be a sign of a future event, often implying that this is a sign of warning. The word comes from the prefix “pre-”, meaning before, and the base “sage,” which does not merely mean wise, but to perceive keenly. Someone who is “sagacious” is wise precisely because that person keenly perceives reality. The word would be used in a sentence like, “In many cultures, the flying of a crow over a barn presaged a poor harvest in the coming year.”

The word “diffuse” comes from roots that literally mean poured away from. The “di-” prefix means away from or down from, and the “-fuse” means to pour. This latter is found in words like “infuse” (meaning, literally, to pour into) and “effusive” (meaning pouring out, implying that someone “pours out” a great amount of something like praise). As a verb, the word “diffuse” means to scatter or to spread out, as when one diffuses a smell into a room or when an idea diffuses through an entire population. The word can likewise be used as an adjective, basically having the meaning of the past participle of the word, namely “scattered.”

In its physical sense, the word "elastic" means bendable or flexible. Hence, we use it to describe things like "elastic bands" that are used for gathering together items. When something is "inelastic" it is not flexible in that way. The "in-" prefix is a privative prefix, meaning that it means not. (This is much like the prefix "un-.") Therefore, something that is "inelastic" could be said to be rigid.

A "chimera" is a kind of mythological creature, but generally the word has come to signify something that cannot possibly occur or exist in reality. Therefore, when something is described as being "chimerical," it is an illusion—something "illusory."

The word "scintillating" comes from the Latin word for "spark" (as in a spark of fire or light). Something that is scintillating has the kind of spark or glow of such a fire. Therefore, it means bright. Something that is "luminous" is very bright or enlightened.

“Macabre” means gruesome, horrifying, or pertaining to death, so "gruesome" is the correct answer. None of the other answers are close in meaning to “macabre”. “Understated” means modest or simple. “Protective” means defensive or shielding. “Panicked” means frightened. “Methodical” means systematic. 

"Opulent" is an adjective that means lavish, and since "sumptuous" means expensive-looking, it is the answer choice closest in meaning to "opulent," so it is the correct answer.

"Impervious" means not letting things pass through, or unaffected by something. One might write, "While everyone else got sick, Michael seemed impervious to germs."

"Sinewy" means tough, stringy, or strong.

"Garish" means too bright and showy, and the correct answer "lurid" means having a color so bright that it is unpleasant. The other choices do not have similar definitions: "delightful" means fun and joyful, "proper" means appropriate, "severe" means harsh, and "frightening" means scary.