Something that is dull lacks excitement. The meaning is often transferred to apply to a person who is “plodding” or unexciting, generally implying that such a person does not have much in the way of intellectual capacities. There is nothing among the options provided that given an antonym for this latter sense of “dull,” so it must be used in the former. (Note that “foolish” and “stupid” are trap answers trying to get you to choose a potential synonym—not an antonym). The opposite of “lacking excitement” is well captured by the common word “stimulating,” which means “arousing interest or excitement.”

Ebony is a very dark brown or black type of tree or the timber taken from it, though it is often used as a noun that means “a very dark brown or black color.” Thus, the best antonym for this word is “white”—as simple as that might seem! Definitely do not read “ebony” as having anything to do with “bones.” Otherwise, you will start to consider all of the other trap answers, which are far from correct.

The word “elite” is related to the word “elect,” which means “select or chosen.” Such people are either the best in a group or at least believe themselves to be. In contrast to such people, one finds the mere “common run of humanity”—those ordinary people who are not members of the elect. While such persons might be forgotten, the best antonym for “elite” is “common,” which captures the sense of “not elite, chosen, select, grand, and / or talented.” Do not be tempted to select “aristocratic” or “regal.” These are trying to trick you into choosing potential synonyms.

Someone who is “emaciated” is extremely thin, perhaps because of malnutrition. Although it is somewhat simple, “plump” is the best antonym for this, as it is the only option that is opposed to the sense of being extremely thin.

Something that is “disproportionate” is either too large or small in comparison with something else. For instance, one could say, “The growth of the stock price was disproportionately higher than the growth in the company’s profit, which was increasing in very humble increments.” Among the options provided, the best contrast to such “disproportion” is “equality,” or “equal.”

When something is enlightening, it gives knowledge or insight into a topic. To “enlighten” is to give such knowledge. In contrast to this, “to confound” someone is to cause confusion. The word comes from the Latin for “to mix with.” The “con-” prefix means “with” and the “-found” portion of this word is related to the “-fus-” portion of “confuse” or “confusion.”

Something that is bizarre is very unusual, as when one says, “He has the most bizarre opinions of anyone I know. They are so extraordinary that they make no sense to me at all.” This is quite the opposite from “ordinary,” which is a suitable antonym.

Betrayal is an act of breaking the trust that someone has placed in you. This is quite the opposite of being faithful. “Fidelity” is the character trait of faithfulness. The word is taken from the Latin for “faith” and is found in the Marines’ motto: “Semper fidelis”—“Always faithful.”

When someone is critical, he or she disapproves of something. For instance, “Kevin was extremely critical of his coworkers, always judging something to be wrong in their work.” This is quite the opposite of “accepting,” which means “to affirm, validate, or approve.”

Someone who is effective is able to produce desired outcomes—desired effects. Such a person could be called successful, efficacious, or powerful. (The word “effective” can also be used in the sense of meaning “convincing” as in an “effective argument” and also “in force” as in “the policy that is now effective”). The only option that functions as an antonym is “unproductive,” which is the opposite of someone who is effective. Unsurprisingly, an unproductive person is someone who is unable to produce outcomes with any particular efficacy.