c. 1200, clergie "office or dignity of a clergyman," from two Old French words: 1. clergié "clerics, learned men," from Medieval Latin clericatus, from Late Latin clericus (see clerk (n.)); 2. clergie "learning, knowledge, erudition," from clerc, also from Late Latin clericus.
Meaning "persons ordained for religious work, persons consecrated to the duties of public ministration in the Christian church" is from c. 1300. Benefit of clergy (1510s) is the exemption of ecclesiastics from certain criminal processes before secular judges; in England it was first recognized 1274, modified over time, and abolished in 1827.
The ability to read, being originally merely the test of the 'clergy', or clerical position, of the accused, came at length to be in itself the ground of the privilege, so that the phrase became = 'benefit of scholarship' [OED]
1670s, "a nun," from clergy + woman on the model of clergyman. Not seriously as "woman pastor, woman of the clerical profession" until 1871; in between it was used humorously for "old woman" or "domineering wife of a clergyman." Clergess as "member of a female religious order" is attested from late 14c.; clergy-feme as "clergyman's wife or woman" is attested from 1580s.
1590s, "pertaining to the clergy," from cleric + -al (1), or from French clérical, from Old French clerigal "learned," from Latin clericalis, from clericus (see cleric). Meaning "pertaining to clerks and copyists" is from 1798.
Clericalism "sacerdotalism, power or influence of the clergy" is from 1849. Clericality "quality of being clerical" is from 1650s.