Of, relating to, or characteristic of Christ; christlike or Christian.
From Christ plus the English adjectival suffix -ly (from Old English -lic). This archaic or poetic form is an earlier alternative to the modern 'christlike.'
Language constantly evolves—'christly' was once a standard way to describe Christ-like qualities, but English speakers eventually preferred 'christlike' because it's clearer and less prone to confusion with adverbs.
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