The term "full feather" is often used to describe something at its peak or highest level. Synonyms for full feather include "at its zenith," "fully bloomed," "in full swing," "at the height of its powers," and "in its prime." Similarly, the word "flourishing" also expresses a state of blooming or thriving, while "thriving" denotes a state of growth and prosperity. Other synonyms for full feather include "vigorous," "robust," and "energetic," which all describe something that is strong and active. Overall, there are many words that can be used in place of full feather to describe a state of excellence or flourishing.