"Proficient" means skilled or competent, so "competent" is the correct answer. None of the other answer choices are close in meaning to "proficient": "flimsy" means fragile and easily broken; "reliable" means dependable; "lucid" means clearly explained; and "cautious" means careful and risk-averse.

"Indolent" means tending to avoid exertion, and "lethargic" means lacking energy or sluggish. These two similar definitions make the words synonyms. 

"Diligent" is an adjective that means putting forth constant effort to accomplish something or persistent. The best choice is "attentive" because it has a similar meaning—putting much effort into caring for something or someone. Considering the other choices, "praiseworthy" means deserving praise, "lucid" means easily understood, "considerate" means thinking of others' feelings, and "perilous" means dangerous.

"Submissive" means docile or obedient to others, so "docile" is the correct answer. None of the other answer choices are close in meaning to "submissive": "combative" means aggressive and inclined to fight; "meager" means inadequate or insufficient; "remote" means at a great distance or away from the cities or populated areas; and "stingy" means cheap or not inclined to spend money.

“Tenacious” means stubborn, not going to let anything stop you, or "determined." As for the other answer choices, “excessive” means in an amount that is more than is necessary or wanted; “congested” means backed up or clogged; “serene” means peaceful and quiet; and “frenetic” means fast-paced and stressed.

“Fervent” means intensely passionate about some particular cause or ideal, so "intense" is the correct answer. As for the other answer choices, “sagacious” means wise; “wanton” means random; “vicious” means cruel and desiring to cause pain; and “simultaneous” means happening at the same time as something else.

“Judicious” means careful and "prudent" when referring to people and reasonably considered when referring to decisions. As for the other answer choices, “robust” means strong and hard to break; “flagrant” means obviously and openly outrageous; “akin” means similar to; and “astute” means clever and observant.

"Amicable” means friendly and good-natured, so "friendly" is the best answer choice. As for the other answer choices, “selfish” means thinking of only oneself instead of others; “selfless” means generous, caring about others more than yourself; “aimless” means without purpose or pointless; and “fortified” means strengthened, reinforced, or protected.

Someone who is “obsequious” is groveling and pays compliments to someone who has power in order to gain that person's favor. This means that "servile," which means excessively subservient and fawning, is the best answer choice. As for the other answer choices, “domineering” means in charge or in control; “abrupt” means happening quickly, suddenly, and without warning; “obnoxious” means rude, loud, and ignorant; and “bereaved” means in mourning for the loss of a loved one.

“Spineless” means lacking gumption, confidence, and autonomy, so "craven," which means weak and afraid, is the correct answer. To provide further help, “whimsical” means silly and quirky; “quarrelsome” means argumentative; “burdensome” means worrisome or arduous; and “loathsome” means deserving of hatred.