"Churlish" is an adjective that means "rude in a mean-spirited and surly way," or "marked by a lack of civility or graciousness." So, we're looking for another adjective that means something like "rude" or "uncivil." While "haughty" seems like a possible choice because someone who is haughty might also be rude, "haughty" specifically means "arrogantly superior and disdainful," not specifically "rude." On the other hand, "vulgar" means "lacking in cultivation, perception, or taste" or "offensive in language," and is the closest synonym to "churlish," and therefore the best answer choice.

The word “sensible” is clearly related to the notion of “the senses” and what can be perceived by them. It is often used to express the fact that someone is “down to earth” or quite “practical”—always keeping things at the level of observable reality, not detached in idealism or grand speculation. Because of these latter usages, the word has become synonymous with “reasonable” in many of its normal usages.

The word “amplify” literally means “to make larger.” The “ampli-” portion is the same as that which is found in “ample” (spacious or plentiful) and “amplitude” (roughly meaning “magnitude,” often used in physics to describe vibrations).   The “-fy” means “to do or make.” The word “amplify” is often used to describe the process of making sounds louder, though it can mean “intensify” in the general sense as well.

The word “legible” comes from the Latin “legere” meaning to read. The English word means clear and readable. It is related to the word “lector,” which means reader. Often people will talk about “legible handwriting,” but the word can be used to describe print words that are likewise readable.

The suffix -clast is of Greek origin, it means break. An "iconoclast" is a critic, someone who tries to break an institution by attacking it. To provide further help, a "fanatic" is someone who cares deeply about something; "vendor," "purveyor," and "peddler" are all synonyms - they all mean seller.

"Anarchy" means chaos, the lack of a political order. As a word it can be easily broken down to its component parts. The prefix an- means without and the root -arch- means leader, chief. So "anarchy" is without a leader, without a government, the lack of political order. 

The “-mersed” portion of this word is related to similar forms found in English words like “submerge” and “emerge.” It is derived from the Latin for to dip. The prefix “im-” is a version of “in.” Although “immersion” can describe the process of dunking someone into water, it likewise can mean that someone is completely absorbed in some activity. Consider a sentence like: “He was immersed in programming, little aware of anything in the world other than himself and his computer.” Likewise, we sometimes speak of people studying languages “by immersion,” that is, by living in the context of the language and using only the language being learned instead of their native languages for communication.

The word “vulnerable” comes from the Latin for wound. With the “-able” prefix, it would mean able to be wounded. Therefore, when someone is “in-vulnerable,” he or she is not able to be wounded. The word “invincible” does not necessarily pertain to wounds, but it does mean unable to be conquered. You may have heard of the famous line attributed to Julius Caesar: “Veni, vidi, vici,” “I came, I saw, I conquered.” The last word, “vici,” is a form of “vincere,” meaning, to conquer. To be “invincible,” is thus to be “un-conquerable.”

From the Latin "delectare," which means to delight (compare with the English cognate "delectable"), a "dilettante" is one who engages in an activity for the sheer enjoyment of it—an amateur or dabbler. Be careful not to confuse this word with "dilatory" (causing delay) or "debutante" (a girl making her "debut" into society).

The word “diffidence” literally means “not having faith” in oneself. The “-fidence” portion of the word is related to other English words pertaining to faith, such as “fidelity” and “confidence.” When someone does not have faith or trust in himself or herself, that person is often bashful or shy due to that lack of confidence. A related word, “diffident” is the adjective form of the word.