na-adjective
manifest; clear (of a divine sign)
Archaic term for a miracle or divine sign being unmistakably clear. Not used in modern Japanese.
古典では、神の御業が灼然と現れたと記される。
In classical texts, it is recorded that the divine work appeared manifest.
na-adjective
Archaic emphatic expression meaning something is extremely obvious. Not used in modern Japanese.
その嘘は灼然としていたので、誰も信じなかった。
The lie was so plain as day that no one believed it.
The reading いやちこ is a gikun (meaning-based reading) assigned to the kanji 灼然. The exact derivation is uncertain; it is an archaic term with no clear modern descendant.