Whenever something is "enormous," it is very big. This "very" is important. Several options, like "big" and "large," do not express this "very." Only "huge" is a word that means very big. Therefore, it is the best option among those provided.

Something that is monotonous repeats without varying, so another word for "monotonous" is "repetitive." Considering the other choices, "loud" means great in volume, "monochrome" means consisting of one color or different shades of one color, and "same" means alike.

The correct answer is "speedy," or in a quick manner, as "swift" means occurring or moving very quickly. "Slow" is an opposite of "swift" and "dance" is not related in meaning to "swift" at all. While to "run" does mean to move quickly, "run" is a verb and "swift" is an adjective, so their meanings are very different.

The word "sluggish" means slow or lazy. "Slow" is the best choice, as it is a part of the definition of "sluggish." Considering the other choices, "stiff" means rigid. While it may seem related, the word "sluggish" describes some sort of motion, though very little, while "stiff" does not. "Active" is an antonym of the word "sluggish." "Slug" is only related because sluggish means slug-like, as in as slow as a slug.

"Nimble" means quick and agile. "Agile" is the best choice because it means easily able to move quickly and is part of the definition of "nimble." Considering the other choices, "robotic" means acting in an unchanging and unemotional manner, like a robot, "correct" means right or true, and "indifferent" means not caring. 

"Idle" means unmoving or not active. "Stationary" is the best choice because it also means unmoving. Considering the other choices, "hidden" means not in plain sight, "deter" means restrain from doing, and "vex" means anger or annoy.

"Regular" is an adjective that means occurring at even intervals, frequent, or usual. So, the answer choice closest in meaning to "regular" is "usual," an adjective that means typically occurring. None of the other answers are close in meaning to "regular": "atypical" is an antonym of "regular" and means not typical; "regulated" means controlled; and "trite" means unoriginal.

“Sluggish” means tired, lethargic and lacking energy.

Someone who is "sluggish" is lazy and slow, so "lazy" is the correct answer. None of the other answer choices are close in meaning to "sluggish": "debilitated" means weakened or hindered; "depressed" means feeling sad over a period of time or having the condition depression; and "dull" means boring or blunt.

The word "mature" or "maturity" are used to describe the character traits that come to something as it ages. In some ways, we talk about "mature" people, but in others, we can talk about "mature" fruits or cheese—cheese or fruits that have "come of age" and are now usesful. A number of the options try to trick you into choosing an answer based merely on age. Remember, though, maturity does not necessarily come with age. For example, you might know someone who is twenty years older than you but who never does any work and always relies upon other people. We would be quite wrong to call such a person mature.

Certainly, we can talk about "emotional maturity," which is a type of maturity. Someone who always gets angry or moody is probably not very emotionally mature. However, another general meaning for "mature" is "dependable." A mature person is someone who accepts responsibilities and can be depended upon to follow through on promises. This is the best option among those options given.