This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The historical origin of 焏 is uncertain. It visually contains 口, 了, 又, and the fire radical 灬, but the exact development is unclear.
With no clear meaning, picture the fire radical 灬 under a jumble of shapes (口, 了, 又) as a mysterious, undefined blaze.
For キョク, imagine a quirky, unknown flame: quirky -> キョク, matching the kanji's obscure nature.