"Listless" means lacking energy and enthusiasm and is therefore most similar in meaning to "lethargic." For clarification, the other four answer choice are all loosely synonyms of one another and antonyms of "listless" and "lethargic."

Something that is "gruesome" is grotesque and horrible. For clarification, mediocre, middling and average are all synonyms that mean in the middle.

"Reckless" means uncareful; Prudent means careful; Destructive means causing damage; Disabled means injured; and Crimson is a shade of red.