A pochemuchka (почемучка) is a person, often a child, who asks a lot of questions. This Russian word comes from “pochemu (почему)”, meaning “why.” A pochemuchka is a person who is asking “why?” all the time.
Also, wissensdurst is a feeling one gets in craving an answer to a burning question or displaying curiosity, inquisitiveness or a unique desire to learn. This German word comes from “wissen” (knowledge) and “durst” (thirst). (added by linguisten)