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.

The word "cogent" is generally used to describe an argument that someone might be making. It means logical or convincing. An example sentence would be, "After he presented the facts, his argument seemed to be quite cogent. Therefore, I agreed with his decision and followed his instructions." Such an argument is also "compelling," meaning something like irresistible—as though the argument is so strong that it cannot be "overcome."

The word "abstract" literally means to pull away from. (Surprisingly, it comes from the same root as the word "tractor.") An abstract idea "pulls away" information from our immediate experience into more general categories of thought. It is therefore somewhat theoretical or conceptual in nature. The "abstract" notion of "human person" is very general and theoretical in comparison with a concrete person who stands directly in front of us.