full ability; one's full potential
Rare literary word referring to a person's full ability or talent, often used in the context of giving someone a chance to demonstrate their capabilities. The expression 驥足を伸ばす means 'to give full play to one's ability'.
He was finally able to give full play to his abilities at his new workplace.
驥 means a swift horse (a legendary steed), and 足 means foot or leg. The compound 驥足 originally referred to the speed of a fine horse, and by extension came to mean outstanding ability or full potential. The exact historical derivation is uncertain, but the word is now rare and literary.