The word “poignant” comes from the Latin for “to prick” or “pierce.” Something that is “poignant” pierces to the heart, often evoking emotions of sadness something that no longer exists or for some regret. For instance, an elderly person might be said to experience poignant memories of his or her youth, spent joyfully with friends who are no longer alive. Among the options provided, only “sorrowful” indicates the sadness brought about by such memories.

"Pusillanimous" and "timorous" both mean fearful or cowardly. "Valiant" means brave or courageous. "Sumptuous" means luxurious or splendid. "Viable" means reasonable or practical. "Prevalent" means accepted or widespread. 

"Lugubrious" means sorrowful or bleak. "Decorous" means appropriate or suitable. "Congenial" means friendly or affable. "Avuncular" refers to something advisable. "Prompt" means on-time or responsive.

"Lackadaisical" and "apathetic" both mean careless or indifferent. "Untoward" means troublesome or improper. "Refulgent" means glowing or brilliant. "Halcyon" means calm or peaceful. "Inchoate" means undeveloped or beginning. 

"Aloof" and "haughty" both mean remote or detached. "Sympathetic" means concerned or caring. "Feckless" means careless or without purpose. "Glib" means slick or smooth-talking. "Diaphanous" means fine or see-through. 

The word “ardent” is related to “ardor,” which means passion or zeal. Both of these terms come from that Latin verb meaning to be on fire. In a sense, you can think of them as expressing “being on fire” emotionally for some project, goal, or aim. When someone is called, for example, “an ardent supporter,” he or she is a strong and zealous supporter of that cause. Likewise, when one “ardently discusses a topic,” he or she does so with great enthusiasm and vigor.

When someone is “overwrought,” that person is excited or anxious. While that might cause someone to be jittery or even annoying, the best option among those given is the mere direct definition, “anxious.” The word would be used in a sentence like, “Having arrived at the long-feared day, Jonathan was so overwrought that he could not even sleep because of his agitated nerves.”

The word “tempestuous” is related to the word “tempest,” which is a strong wind storm. When applied to a human person, it implies that the person has a very strong emotional disposition. Someone could say, “John had an extremely tempestuous attitude, often screaming at his subordinates and always arguing with someone.”

The word “vacant” is related to the word “vacuum,” meaning “empty space.” Sometimes, you will hear an expression like “a vacant lot” to describe a piece of land that has nothing built on it (and perhaps is abandoned and unused). The word can also be applied to the expression that a person has. When someone shows a “vacant expression,” he or she has a “blank stare.” Often this implies that there is no emotion expressed at all.

"Jubilant" is an adjective defined as "feeling or expressing great happiness and triumph." While all of the answer choices describe moods or emotions, only "gleeful," an adjective that means "exuberantly or triumphantly joyful," is a synonym of "jubilant," so "gleeful" is the correct answer.