"Unctuous" and "oleaginous" both mean oily or slick. "Blunt" means straightforward or candid. "Ingratiating" means fawning or servile. "Tendentious" means biased or prejudicial. "Tortuous" means twisted or complicated. 

"Sinewy" and "brawny" both mean tough or stringy. "Germinal" means budding or initial. "Irksome" means annoying or irritating. "Mutinous" means rebellious or defiant. "Personable" means friendly or sociable. 

You might think of the word strident as meaning “strong” or “determined.” The word is often used in this manner and loosely can mean this, merely presenting an opinion in a forceful manner. The first meaning of the word is “rough” or “grating,” as in a “grating and loud sound.” Thus, someone who defends a position very strongly and with much passion might become strident in voice, that is, harsh sounding in vocal tone.

"Impervious" means not able to be penetrated, so "impenetrable," which also means unable to be penetrated, is the correct answer. "Porous" is an antonym of "impervious"; it means having holes through which things can pass. None of the other answer choices are related in meaning to "impervious": "conceited" means self-centered or full of oneself; "incessant" means continual or without pause or break; and "delectable" means tasty or delicious.

"Shiny" is an adjective that means bright or glossy in appearance. "Glossy" is therefore the best choice, since it is a part of the definition of "shiny." Considering the other choices, "dull" is an antonym of "shiny" that means lacking polish or color, "alluring" means very attractive, "abhorrent" means detestable, and "persistent" means dogged and resolute when referring to a person lasting for a long time when referring to things.

“Noxious” means toxic or "poisonous." “Innocuous” means harmless; “hospitable” means welcoming; "habitable" refers to areas and means able to support life; and "fragrant" means having a pleasant smell.

“Odious” means disgusting, repulsive, or "repellent." As for the other answer choices, “endearing” means causing others to feel affection for one in one's interactions with them; “attractive” means good-looking; “coherent” means able to be understood and making sense; and “meddlesome” means interfering or getting in the way.

“Opulent” means luxurious, extravagant and very fancy, or financially rich. As for the other answer choices, “foreboding” means ominous; “disconcerting” means troubling or worrying; “penitent” means showing regret and wanting forgiveness; “indiscriminate” means done at random, aimless, and arbitrary.

“Austere” means severe and grim, so "dour," which means stern and solemn, is the correct answer. As for the other answer choices, “dire” means serious or terrible; “livid” means furious; “loyal” means faithful to a person, group, or cause; and “lucid” means clear and understandable.

“Incongruous” means out of place or "inappropriate." As for the other answer choices, “apt” means appropriate and right and is an antonym of "incongruous." “Discontinuous” means intermittent and containing gaps; “self-serving” means doing something to benefit only oneself; and “winsome” means charming.