"Withhold" is a verb that means either "refuse to give (something that is due to or is desired by another)" or "suppress or hold back (an emotion or reaction)," so we need to pick out an answer that means something like "refuse to give" or "suppress." "Proffer," then, cannot be the correct answer because "proffer" is a verb that means "hold out (something) to someone for acceptance; offer," making it an antonym, not a synonym, of "withhold." "Retain," however, is a verb that can mean "continue to have (something); keep possession of," and because "retain" is the answer choice closest in meaning to "withhold," "retain" is the correct answer.

"Grovel" is a verb that means either "to kneel, lie, or crawl on the ground," or "to treat someone with too much respect or fear in a way that shows weakness in order to be forgiven or to gain approval or favor." So, we need to pick out a verb that means something like "to kneel" or "to treat someone with too much respect or fear to gain approval." While "pardon" may look like a potentially correct answer, "pardon" means "forgive or excuse (a person, error, or offense)," so while someone may grovel to a person who can pardon them for past offenses, "pardon" does not mean the same thing as "grovel," so "pardon" cannot be the correct answer. "Crawl," however, is synonymous with the first meaning of "grovel," so "crawl" is the correct answer because it is the answer choice closest in meaning to "grovel."

"Mar" means to spoil the appearance of or disfigure. A scar might mar someone's face or a wooden table could be marred by a deep scratch.

"Languish" means to weaken and become feeble, so it is most similar in meaning to "deteriorate," which means to waste away. "Enliven" and "flourish" both have positive connotations and mean to prosper or to come alive. "Stagnate" means to remain without growth or movement, and "concern" (which means consternation) is unrelated in meaning to "languish."

"Dawdle" is most appropriate here because both "dawdle" and "tarry" mean linger or procrastinate. "Hasten" is an antonym of "dawdle" that means to move more quickly or to cause to occur sooner, while "frustrate" can mean thwart or spoil. "Scramble" means clamber or muddle, and "maintain" means to continue or to persist.

"Douse" means submerge briefly in water or throw liquid at, so "drench," which means soak, is the best match. "Drain" means remove liquid from something, making it an antonym, or opposite, of "douse."

"Taint" means contaminate, so "contaminate" is the correct answer.

"Hamper" means obstruct or hinder. For example, one might write, "Excessive noise can hamper a teacher's effectiveness in the classroom." So, "hinder" is the correct answer.

To "hasten" means to hurry or to rush. For example, one might write, "The woman hastened her speech as she realized she was running out of time to communicate what she wanted to say." So, "hurry" is the correct answer.