chortle(verb): laugh merrily, laugh in a noisy, gleeful way.

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exacerbate(verb) :make worse.

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banal(adjective): repeated too often, overfamiliar through overuse.

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decorous(adjective): characterized by good taste in manners and conduct.

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culminate(verb): reach a climax or point of highest development.

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I hope this helps you if you are preparing for GRE exams.