Find out the word that conveys the given meaning : Mental weariness from lack…

Step-by-Step Explanation
To identify the correct word for the phrase "Mental weariness from lack of interest," we must examine the definitions of the given options:

Analyze the phrase: The phrase describes a state of boredom, listlessness, or dissatisfaction resulting from a lack of interest or excitement.

Evaluate the options:

Exile: Refers to the state of being barred from one's native country, typically for political or punitive reasons.

Ennui: A French term adopted into English that specifically defines a feeling of listlessness and dissatisfaction arising from a lack of occupation or excitement; it is the precise definition of "mental weariness from lack of interest."

Enunciate: Means to pronounce words clearly or to express a proposition in a definite or systematic way.

Expiate: Means to atone for guilt or sin.