To become full-fledged; to be fully grown and capable; to have fully developed capabilities or strength.
经过多年的学习和实践，他现在羽毛丰满了，可以独当一面了。
After years of study and practice, he is now full-fledged and can work independently.
Era:
Ancient
Frequency:
Story:
During the Western Han Dynasty, after Liu Bang became emperor, he established Liu Ying, the son of Empress Lü, as the crown prince. However, because he favored Consort Qi, he wished to replace Liu Ying with Liu Ruyi as the heir.
Empress Lü sought advice from Zhang Liang, who suggested that Crown Prince Liu Ying invite the Four Sages of Mount Shang.
When Liu Bang saw that the Crown Prince was assisted by the Four Sages of Mount Shang, signifying that his 'wings were full-fledged' (i.e., his power base was firmly established), he abandoned the idea of appointing another crown prince.
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