"Dour" is an adjective that refers to someone's manner or appearance and has a few different meanings, including gloomy and austere. While "dilapidated" sounds like it might be a good answer choice, it means in poor condition due to having been neglected over time—not quite what we're looking for. "Grim," on the other hand, can mean somber or gloomy and is the closest in meaning to "dour," so it is the best answer choice.

The word “prudent” has perhaps received a bad sense in its standard usage by most English-speakers. One will at times speak of “prudent” people who know how to work things to their gain. For instance, someone might be called “prudent” for keeping silent about opinions instead of insulting someone who might give him or her a job; however, the word “prudent” is of much nobler origins, meaning discerning or even wise in practical action. For this reason, among the options provided, the best option is “judicious,” meaning judging well. This meaning will cover the more negative uses but likewise applies to the nobler notions of “prudence.”

"Capricious" means changing one's mood in a fickle, unpredictable manner, so the answer choice that is its best synonym is "fickle," or changing frequently.

The word “judicious” is related to “judgment,” but do not let that lead you to the law-related words like “legal,” “illicit,” and “tribunal.” When someone is “judicious,” he or she has and exercises “good judgment.” Such a person could be called “prudent,” meaning he or she is wise in a practical manner.

"Capricious" means unpredictable, so both planned and predictable are incorrect, because they are antonyms for capricious. "Condescending" means to lower in position, and "amusing" involves humor, so the best answer choice is "impulsive."

"Ostentatious" means conspicuous, flashy, or showy. "Mellifluous" means smooth and sweet-sounding. "Pedantic" means overly-precise or bookish. "Pejorative" means negative or belittling. "Resolute" means determined or strong-willed.

"Quixotic" is an adjective that means "exceedingly idealistic; unrealistic and impractical" and derives from Cervantes's literary character Don Quixote. While "quotidian" may look like a potentially correct answer choice simply because both "quixotic" and "quotidian" begin with "q," "quotidian" means "of or occurring every day," so it cannot be the correct answer. "Idealistic," which means "characterized by idealism; unrealistically aiming for perfection," is the best answer choice because it is closest in meaning to "quixotic."

"Placid" is an adjective meaning either "not easily upset or excited" when used to describe a person or animal and "calm and peaceful, with little movement or activity" when describing a place or stretch of water. "Levelheaded," an adjective that means "calm and sensible," is the answer choice closest in meaning to "placid," so it is the correct answer.

A "morose" person is of a sullen temperament, often negative and depressing to be around. Among the options provided, the only decent synonym is “gloomy.” The words “conventional” and especially “virtuous” might tempt you given that “morose” looks like “moral.” While it actually is distantly related to these other words, do not be tricked so easily!

"Fractious" means "irritable" and quarrelsome.