full of curiosity; having a strong interest in many things. A descriptive (na-adjective) phrase often used for personalities, especially children.
子どもは好奇心旺盛で、外の世界を知りたがる。
Children are full of curiosity and want to learn about the outside world.
彼女は好奇心旺盛だから、新しいことにすぐ挑戦する。
She's very curious, so she quickly tries new things.
研究職には好奇心旺盛な人が向いていると言われる。
People who are full of curiosity are said to be suited to research jobs.