Antonyms

Rue means to bitterly regret something. Rejoice, which means to feel great joy, is the correct antonym.

Insularity refers to an ignorance of or lack of interest in cultures or ideas outside one's own experience. Tolerance is the best antonym here.

A libertine is a person who rejects accepted moral standards. An ascetic is someone who practices severe self-discipline and abstention from indulgences, making it the correct antonym.

Verdant means green with grass or other rich vegetation. Sere means dry or withered, which is the correct antonym.

In this context, 'bent' refers to a natural talent or inclination. Ineptitude, which means a lack of skill or ability, is the correct antonym.

Stolid means calm, dependable, and showing little emotion. Lively is the most appropriate antonym as it implies energy and animation.

Obstinate means stubborn or refusing to change one's opinion. Tractable means easy to control or influence, making it the correct antonym.

"Imperceptible" 

Torpor refers to a state of physical or mental inactivity or lethargy. Vigour is the opposite, representing physical strength and good health.

Grievous means very severe or serious. Slight means small in degree or intensity, making it the correct antonym.

Inimitable means so good or unusual as to be impossible to copy. Ordinary means common or standard, which is the correct antonym.

Caustic means sarcastic in a scathing and bitter way, or able to burn. Innocuous means not harmful or offensive, making it the correct antonym.

Palpability refers to something being able to be touched or felt. Intangibility means unable to be touched or grasped, which is the correct antonym.

Discrete means individually separate and distinct. Continuous means forming an unbroken whole, which is the opposite.

Bad is a general term for something of poor quality or low standard. Profane is a specific type of 'bad' (vulgar or irreverent), but in some contexts, it is used to describe something morally corrupt or base, making it the best fit among the choices.