Webster's Revised Unabridged Dictionary · 1913

Unchristian

Unchristian , adjective

[Prefix un- not + Christian.]

1.
Not Christian; not converted to the Christian faith; infidel.
2.
Contrary to Christianity; not like or becoming a Christian; as, unchristian conduct.

Unchristian , transitive verb

[1st pref. un- + Christian.]

To make unchristian. [Obsolete] — South