clergy n.

c. 1200, "man ordained in the ministry, a priest, an ecclesiastic," from Old English cleric and Old French clerc "clergyman, priest; scholar, student," both from Church Latin clericus "a priest," noun use of adjective meaning "priestly, belonging to the clerus" (see cleric).

Modern bureaucratic usage is a reminder of the time when clergy alone could read and write and were employed as scribes and account-keepers by secular authorities. In late Old English the word also can mean "king's scribe; keeper of accounts." And by c. 1200 clerk took on a secondary sense in Middle English (as the cognate word did in Old French) of "man of letters, anyone who can read or write."

This led to the senses "assistant in a public or private business" (c. 1500), originally a keeper of accounts, also "officer of a court, municipality, etc. whose duty it is to keep its records and perform its routine business" (1520s), and later, especially in American English, "a retail salesman" (1790). Meaning "an employee who registers guests in a hotel" is by 1879.

"member of the clergy, a man in holy orders," 1570s, from clergy + man (n.).

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.