Synonyms

affable & courteous

A deterrent is something that discourages or prevents an action, which is the same as restraint of action. Uncertainty means doubt, Objection means opposition, Deviation means departure from a standard.

Dogmatic means asserting opinions in an arrogant or stubborn way, which is the same as being excessively opinionated. The other choices don't capture this meaning.

digressive, shifting from one subject to  another

This is the correct option.

This is the correct option.

Amicable means characterized by friendliness and absence of conflict or tension. Harmonious directly parallels this - both describe peaceful, cooperative relationships.

Dregs refers to the sediment or solid waste that settles at the bottom of a liquid, or metaphorically to the least valuable parts of something. Debris means scattered pieces or rubbish, making it the closest match among the options. Cream (the valuable part) and power are opposites of what dregs represents.

To waive means to voluntarily give up a right, claim, or privilege. Relinquish means to voluntarily cease keeping or claiming something; to give up or let go of. These are nearly identical in meaning - both involve voluntary surrender of something one could claim. Restrict is the opposite, while permit and admit are unrelated concepts.

Browbeat means to intimidate, discourage, or coerce someone through stern, harsh, or abusive words/behavior. Intimidate is the perfect match - both involve making someone feel fearful or timid to compel compliance. Challenging is neutral; ambitious refers to drive; tarnish means to damage reputation.

Elan refers to distinctive energy, style, enthusiasm, or vigor in someone's manner or approach. Flair means a special instinctive ability or distinctive stylish elegance. Both words capture the idea of doing something with distinctive style and energy. Spiritual and inspiration are too abstract, while boredom is the opposite.

Parley means to hold a conference or discussion with an opposing side, typically to negotiate terms or resolve disputes. Discuss is the correct synonym - both refer to talking through issues. Sweeten (to make more appealing) and race are unrelated. Note: Option B has a spelling error.

Buckle is a polysemous word with multiple valid meanings: (1) to fasten with a buckle, and (2) to collapse or bend under pressure/strain. Crumple (3) means to collapse or crush, which matches the second meaning. Fasten (4) matches the first meaning. Dislodge and become tense are unrelated.

Blaze has multiple meanings: (1) a distinctive mark made on a tree (often to mark a trail), and (2) a large, burning fire. Fire (4) is a direct synonym for the second meaning. Ennui (boredom) and flood are completely unrelated to blaze. Tree marking is the less common meaning but still valid.

Gauche means lacking in social grace, awkward, tactless, or unsophisticated in behavior. Tactless is the perfect synonym - both refer to lacking social skill/sensitivity. Vain and rich are about different qualities, while polished is the opposite of gauche.