colleague ("brother" in the same craft, occupation, or society)My co-brethren of the quill.
1900, Arthur Francis Leach, Report on the manuscripts of the corporation of Beverley, At the death of the co-sisters of the Guild, every co-brother of the Guild to be present
2007, Sethi, A Handbook Of Standard English And Indian Usage: Vocabulary And Grammar, If your wife doesn't have a sister, you just can't have a co-brother.