This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
曔 combines 日 (sun) with 敬, but the historical development and original meaning are uncertain. It may have been a rare character for brightness or drying, but this is speculative.
The sun 日 beside 敬 suggests light or respect, but the exact meaning is unclear. Picture the sun shining respectfully on something, perhaps drying it.
For ケイ, imagine the sun (日) casting a ray of light shaped like the letter K, which stands for ケイ. The K-ray dries the morning dew.