"Flagrant" means obvious or unconcealed, so "obvious" is the correct answer. "Hidden" is an antonym of "flagrant"; it means not obvious or concealed. "Knowledgable" means knowing a large amount of information about a certain subject or smart. "Flimsy" means fragile or easily broken. "Exuberant" means excited or lively.

The adjective "cognizant" means aware of. Additionally, "ominous" means suggesting something bad will happen, portentous, threatening; "deleterious" means causing harm, injurious.

Controversial means giving rise to public disagreement, or disputed.

"Glib"means speaking a lot but in an insincere and flippant way, so "flippant," meaning facetious and rude, is the correct answer.

The adjective "esoteric" means understood by only a small number of people, arcane and privileged knowledge. The correct answer is therefore "arcane." Additionally, "ingenuous" means naive, easily misled by others; "truculent" means aggressive, quick to anger, eager to fight; "torpid" means inactive, sluggish, lacking energy; "pervasive" means spread throughout.

"Absurd" means unreasonable or ridiculous. "Amiable" means friendly. "Shocked" means to be surprised. "Detached" means not connected or unconcerned. "Vague" means not clear or hard to understand.

"Arcane" means secret, mysterious, or understood by very few people. The Latin root word, "arcanus," means secret or hidden.

"Unadulterated" refers to something that is pure; something that has not been tampered with. The other answer choices have similarly positive connotations but don't quite capture this shade of meaning. "Elegant" may refer to something luxurious, while "special" and "top-notch" refer to something of good quality. "Considerate" is not at all related to the word "unadulterated."

"Doubtful" means hesitant, unsure, or not likely true, so "uncertain," an adjective that means hesitant or unsure, is the correct answer. None of the other answer choices are close in meaning to "doubtful" and "uncertain": "affable" means friendly and easy to get along with; "pleasant" means providing joy or happiness; "considerate" means kind and thoughtful; and "proper" means suitable or correct.

"Authoritative" and "official" are synonyms. They refer to an object's standing or reputation as being of the highest official or institutional caliber. The other words might appear similar but do not have closely related meanings. "Authorial" refers to the something (usually intention) pertaining to an author.