Biblical verses – The vast majority of the occurrences of both the verb כהן and the noun כֹּהֵן refer to a priest who serves either Hashem or an idolatrous god.
Additional data –
2. Be adorned
Biblical verses – In Yeshayahu 61:10yekhahen does not mean to serve as a priest, but rather to be adorned or clothed (perhaps, like a priest). See also Shemuel II 8:18 where the noun כֹּהֵן refers not to a priest but to a different type of distinguished individual.