This is extremely likely to be an OCR error, as the sentence is illogical, ungrammatical, and certainly does not have anything to do with the definition it's paired with.
The original sentence as printed is much more likely to have read something like this:
Jezrael could see Her Eminence paling as she strove for greater calm.
In this case, "Her Eminence" is a title used of some noblewoman (meaning roughly the same as "Her Highness" etymologically, but presumably used in slightly different cases), although that's not one in common usage, as far as I know, in Britain, which makes this a bit dubious. (But since Jezrael is not a commonly used name in English, this may actually fit well, if the citation is from some fictional source that makes use of unusual titles and names.) "Paling" is a verb: "to pale" is to change colors toward light or white hues.
Alternatively, supposing a more substantial error in the software, it may have read like this:
Jezrael could see her countenance paling as she strove for greater calm.
In this case it just means that a lady's face ("countenance", an old-fashioned word) was becoming pale in the process of trying to keep calm.