bright, shining, brilliant
煜 centers on bright, radiant light: something shining or brilliant, often with a sense of warmth or fiery glow.
煜 combines 火 (fire) with 昱, which likely contributes both sound and the idea of brightness or daylight. The exact historical development is uncertain.
Fire 火 on the left and 昱 (a shape associated with sunlight) on the right: imagine a blazing fire that shines as brightly as the sun, making everything brilliant.
For イク, picture a single bright spark that makes you say 'eek!' in surprise: 'eek!' -> イク, and the fire's brilliance is startling.