Definition of "unchristian"

I hope I may never again be in a state of mind so unchristian as the mental frame in which I lived for some weeks, respecting the memory of Master B. [His bell rang] two nights out of three, until I conceived the happy idea of twisting Master B.‘s neck […]

1859, Charles Dickens, The Haunted House

Arius […] eventually died obscurely, reputedly as the result of an acute attack of dysentery in a latrine in Constantinople, which circumstance afforded his enemies some unchristian pleasure, and was eventually commemorated with exemplary lack of charity in the Orthodox liturgy.

2009, Diarmaid MacCulloch, A History of Christianity, Penguin, published 2010, page 215