learn, striving, effort
肄 centers on the process of learning through persistent effort: studying, striving, and putting in work to master something.
肄 is a relatively rare character. It appears to combine 矢 (arrow) with 聿 (a hand holding a brush), possibly suggesting the discipline of learning or striving, but the exact historical development is uncertain.
The left side 矢 is an arrow, and the right side 聿 looks like a hand holding a brush. Picture an archer practicing tirelessly, or a scholar writing with focused effort—both striving to learn and improve.
For イ, imagine an eager student saying 'Eee!' with effort as they finally understand a difficult lesson: 'Eee!' -> イ, capturing the striving moment.