What is difference in meaning of eager ,curious ,enthusiastic?

Eager means having or showing keen interest or intense desire or impatient expectancy; "eager to learn"; "eager to travel abroad"; "eager for success"; "eager helpers"; "an eager look"

Curiosity means is an emotion related to natural inquisitive behavior such as exploration, investigation, and learning, evident by observation in human and many animal species. The term can also be used to denote the behavior itself being caused by the emotion of curiosity. As this emotion represents a drive to know new things,.
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Enthusiastic means having or showing great excitement and interest. It meant inspiration or possession by a divine afflatus or by the presence of a god.