fledgling
(also fledgeling)
https://gyazo.com/33176bbd670497ddef5f1b349a1ad293
noun
a young bird that has just fledged.
飛ぶことを習い始めた, 羽の生えたばかりの〈ひな鳥〉
usually as modifier a person or organization that is immature, inexperienced, or underdeveloped:
できたばかりの〈組織･システムなど〉; 駆け出し［経験不足］の〈人〉, 青二才
e.g. the fledgling democracies of eastern Europe.
ORIGIN
mid 19th century: from the obsolete adjective fledge (see fledge), on the pattern of nestling.