Antonyms

Overthrow means to remove forcibly from power or to destroy an established system. Institute means to establish, create, or start an organization or system, making it the direct antonym.

Subvert means to undermine the power and authority of an established system or institution. Elevate means to raise or lift something up, or to promote someone to a higher rank or status. In the context of authority, elevating or supporting a system is the opposite of trying to undermine it.

Jeopardise means to put something into a situation where there is a danger of loss, harm, or failure. Redeem can mean to save or rescue something from a state of being lost or neglected. While not a perfect antonym in all contexts, it is the best fit among the options for recovering or saving something from risk.

Dull is the opposite of Flashy. 

Flagitious describes someone who is shamefully wicked or villainous. Honest is the correct antonym as it implies being virtuous and truthful. Notorious is a synonym, while sadist and lifeless are not direct opposites.

Flexible refers to something that is able to bend easily without breaking or someone who is adaptable. Stiff is the correct antonym, describing something rigid and difficult to bend. Strong, viable, and rational do not directly address the property of flexibility.

Fierce describes something violent, aggressive, or intense in nature. Gentle is the direct antonym, representing a mild, kind, or calm temperament. Aggressive and intense are synonyms, while troubled is unrelated.

Frenzy is a state of wild excitement or uncontrolled activity. Calmness is the opposite, representing a state of peace, quiet, and stability. Agitated, fury, and madness are all synonyms or related to the state of frenzy.

Fractious means irritable and quarrelsome, often used to describe someone who is difficult to control. Temperate means showing moderation or self-restraint, making it the most suitable antonym. Fragile, violent, and righteous do not capture the opposite of an unruly temperament.

Forward indicates a direction toward the front or onward progress. Backward is the direct opposite, indicating a direction toward the rear. Bold, send, and promote are unrelated to the directional meaning of forward.

Fugitive, when used as an adjective, can describe something that is fleeting or quick to disappear. Permanent is the direct opposite, describing something intended to last indefinitely. Brief, transient, and fleeting are all synonyms of fugitive in this context.

Gaudy describes something that is extravagantly bright or showy in a tasteless way. Modest is the opposite, suggesting something plain, simple, or unassuming. Garnish and ornate are more closely related to being decorative, while fatuous means silly or pointless.

Frugal means being sparing or economical with regard to money or resources. A spendthrift is a person who spends money in an extravagant and irresponsible way, making it the perfect antonym. Miserly and stingy are synonyms, while careful is a related but not opposite term.

To gather means to bring together or assemble people or things. To scatter means to throw or move in various random directions, which is the direct opposite action. Collect and amass are synonyms, while patent is unrelated.

General refers to something that is widespread or common. Rare is the correct antonym as it describes something that is not found or seen very often. Category and kind are nouns related to classification, and surplus refers to an excess amount.