Definitions of powerful:

• adjective:   having great power or force or potency or effect

  Example: "The most powerful government in western Europe"

• adjective:   displaying superhuman strength or power
• adjective:   strong enough to knock down or overwhelm
• adjective:   having the power to influence or convince
• adjective:   (of a person) possessing physical strength and weight; rugged and powerful

  Example: "Powerful arms"

• adverb:   (Southern regional intensive) very

  Example: "It is powerful humid"