To "elucidate" is to explain clearly. The root is “lucid” which refers to light, both actual light and light meaning wisdom or knowledge. So to "elucidate" is to give clarity to a subject.

The correct answer is "obfuscate is to confusion." "Obfuscate" means to make something unclear or confusing. So to "obfuscate" is to bring confusion to a subject.

To "sully" is to make dirty or impure. It can be a literal meaning, as in “The pollution from the mill sullied the once pure river,” or it can also have a more figurative meaning, as in “The rumors of cheating sullied the soccer player’s good name.” So there is a connection between sully and reputation (to sully is to corrupt one’s reputation) but it isn’t the same connection as elucidate has to clarity.

Engage and end don’t have much of a connection, and surely not “to engage is to give end to something.” To engage is to occupy (“I can’t see the mayor right now because I’m engaged in a meeting.”) or to interest ("His lecture engaged the curiosity of the students.")

To "stunt" means to hinder or lessen growth. (Malnutrition will stunt the growth of children.)

To "disinfect" will hinder or lessen bacteria. (Just as stunting growth doesn’t necessarily mean to stop all growth, to disinfect does not necessarily eliminate all bacteria; have you ever read the packaging that says “Kills 99.9% of germs?”)

To "reiterate" means to say something again, so "reiterate" doesn’t mean to hinder or lessen repetition. To "enamor" means to fill with affection and love, so enamor doesn’t mean to hinder or lessen affection.

"Migrate" means to move to one region, country, etc. from another. Although certain animals migrate in a certain season,migrate doesn’t mean to hinder or lessen a season, so it isn’t the answer. 

At first look, wedding and marriage might seem like synonyms. But here’s a better connection: A "wedding" is the formal ceremony that begins a marriage.

Is an inauguration the formal ceremony that begins a term? It is. An "inauguration" is a ceremony to mark the beginning of something, especially the formal admission of someone into office, as in the beginning of the term of office of the President of the United States. (In the United States, in the year of a presidential election, Inauguration Day is on January 20th.)

Is a "monarchy" the formal ceremony that begins a "coronation"? No. It’s more the other way around. A "coronation" is the crowning ceremony of a king or a queen, which begins his or her monarchy, or rule.

Is "piety" the formal ceremony that begins a religion? No. "Piety" means the quality of being religious or pious, but it is not the formal ceremony that begins a religion.

Is a "funeral" the formal ceremony that begins a death? Let’s hope not! The death occurs before the funeral.

Lastly, a "gown" is not the formal ceremony that begins a bride; a gown may be worn by a bride, but it isn't a ceremony beginning a bride.

To "debase" means to humiliate and insult, or to reduce the value of something. So, if "debase" means to reduce "value," what does "decompress" involve the reduction of? To "decompress" means to reduce the pressure within something, so the correct answer is "pressure."

"Trifle" means having little "importance." So, a "trifle" is something that lacks "importance." Which of these is something that a "madman" lacks? The correct answer is "sanity," or the ability to behave rationally. Additionally, "vigor" is strength and health. 

A "sadist" is someone who derives pleasure from causing pain to others. So, a "sadist" is primarily concerned with "cruelty." What is a "sybarite" primarily concerned with? Well, a "hedonist" is omeone who is self-indulgent and seeks "luxury." Additionally, "scruples" are misgivings, doubts about something; "dormancy" means a state of inactivity; "commendation" means award, certificate given in recognition of accomplishment; "efficacy" means how effective something is, how likely something is to work as intended.

"Psychosis" is an extreme mental disorder that manifests in a loss of "reality." So, if someone with "psychosis" has lost touch with "reality," what has someone with "aphasia" lost? The correct answer is the ability of "speech." 

A "heretic" is a person who holds an opinion that is at odds with the general way of thinking, or a dissenter.

"Acolyte" means an assistant or follower.

A "crony" is a friend or companion.