Un-fledged means inexperienced or immature, so antonyms for this word would include terms that describe someone who is experienced and skilled. Examples of antonyms for un-fledged include practiced, accomplished, seasoned, mature, and proficient. These terms indicate someone who has a considerable amount of knowledge and experience in a particular area, and who has developed the skills necessary to excel in that area. While someone un-fledged may be able to learn and grow into a particular role, these antonyms suggest someone who has already achieved a level of mastery in their field. They are skilled and accomplished, having honed their abilities through practice and experience.