"Repertoire" means a collection, an inventory; often it means a stockpile of skills or knowledge.

"Alteration" means a change, a modification or a revision. 

"Occurrance" means something that happened, something that occurred; a situation.

"Meeting" means a gathering, a talk; when people group together for a purpose.

"Sensation" means a feeling, a perception or an emotion.

"Irritation" means "inflammation," or a rash; it can also mean a disturbed mental state.

"Happiness" means bliss, satisfaction or contentment.

"Opportunity" means a chance for something, favorable circumstance, a moment.

"Property" means possessions, equity or goods.

"Context" means setting, climate, background.

The correct answer is "essence." 

"Gist" is a noun that means the substance or essence of a speech, text or dialogue.

"Aversion" means dislike, opposition, antagonism. 

"Kindness" means compassion, benevolence, humanity. 

"Mettle" means bravery, caliber or courage.

"Chemistry" means attraction or charm in addition to being a field of natural science.

"Wit" means mentally sharp, funny, or clever and humorous.

"Pigment" means color, dye or stain. 

"Desert" means arid land. 

"Molecule" means a very small piece, a fragment of something, a particle of something. 

"Debt" means money that is owed to others.

"Paper" means the physical object that we write on, or it can mean a written article or essay. 

Constrictive means something is restrictive.

"Limber" is an adjective that means "flexible" or "bending easily," so we need to pick out another adjective that also means "flexible." While "stretched" may look like a good answer because "flexible" means "able to stretch," "stretched" does not mean "flexible," so it can't be correct. "Lithe," on the other hand, means "characterized by flexibility and grace," and since it is closest in meaning to "limber," it is the correct answer.

“Grubby” is an adjective that means either “dirty; grimy” or “disreputable; sordid.” So, we need to pick out an answer choice that means something like “grimy” or “disreputable.” That means that “spotless” cannot be the correct answer, because “spotless” is an adjective that means “absolutely clean or pure; immaculate,” making it an antonym, not a synonym, of “grubby.” “Filthy,” however, is an adjective that can mean “disgustingly dirty,” and because “filthy” is the answer choice closest in meaning to “grubby,” “filthy” is the correct answer.

"Arid" means dry; Moist means slightly wet; Inundated means flooded; Desert is a place that has sand and is dry; and Outer space it the area outside the earth's atmosphere.

"Torrid" means scorching hot or extremely challenging. In this instance the best synonym for one of those meanings is “stifling” which means uncomfortably hot. For clarification, a dispute is an argument or disagreement; mediocre describes something that is average in a negative way; whimsical means silly and quirky; frigid means very cold, and is an antonym of stifling and torrid.