"Preternatural" and "anomalous" both mean unusual or abnormal. "Germane" means appropriate or applicable. "Munificent" means giving or generous. "Stupefying" means stunning or amazing. "Voluminous" means ample or vast. 

The “pot-” portion of this word is derived from the Latin for able and also power. It is found in many English words like “impotent,” “potency,” “omnipotence,” and “potential.” Someone might say, “The speech was extremely potent in stirring the emotions of the crowd; soon, everyone was marching according to the instructions of the speaker.” Among the options provided, “forceful” best conveys this sense of “power.”

When something is futile, it accomplishes nothing. For example, one could say, “No matter how long Thomas spent in the gym, it felt futile, for he was always unable to lift his goal amount of weights.” When something is “ineffectual,” it is “unable to have an effect.” The word is thus somewhat like “ineffective.”

"Inexorable" is an adjective that means "impossible to stop or prevent," or when describing a person, "impossible to persuade by request or entreaty." So, neither "preventable" nor "persuadable" can be the correct answer because each of those words is an antonym of "inexorable," not a synonym. The correct answer is "unstoppable," an adjective that like "inexorable" means "impossible to stop or prevent."

Both "miniscule" and "modicum" mean a small amount so they are not correct. "Lucid" means clear, and a "hedonist" is someone who lives for pleasure. "Gargantuan" is a synonym for huge.

The word “economical” is not the same as “economic,” which can mean “pertaining to finances or wealth.” Instead, it can mean “someone who is thrifty or careful with money” as well as “something that is inexpensive but useful” such as “an economical house.”

The word “sheer” is not the same as “shear.” The latter means “to cut” or “to shave,” often speaking of the cutting of wool from sheep. The word “sheer” means instead “complete” or “sudden.” The latter would be used to describe something like a cliff that is completely vertical—“a sheer drop.” Likewise, it can mean “complete,” “utter,” “or “absolutely” when used in an expression like, “The plan was not merely questionable; it was sheer madness to do something so insane.”

“Affluent” means very wealthy. It is the opposite of “impoverished,” which means very poor. “Despicable” means evil and wicked; “comely” means very cute and beautiful; and “winsome” means charming and appealing.

“Colloquial” means informal or conversational and refers to language or writing, so "conversational" is the best answer choice. As for the other answer choices, “irredeemable” means unable to be redeemed or so bad that it cannot be forgiven; “plausible” means believable as being potentially true or succeeding; “irrational” means not rational, not logical, and thinking with emotions; and “illicit” means against the rules or illegal.

"Caustic" means corrosive when describing substances or scathing when describing communication and speech. So, "derisive," which means disdainful and scathing, is the correct answer. “Plump” means fat, chubby, and round; “euphoric” means in a state of intense happiness; “obscure” means esoteric or unclear; and “obligatory” means mandatory.