Lawyer
From Memory Alpha, the free Star Trek reference.
A lawyer (also known as an attorney, or advocate) was a person who represents the interests of a person, for example, in a court of law. They were also hired for to either defend or prosecute in a court or court martial case. (TOS: "Court Martial")
The role continued to exist in the 24th century.
On Earth by the year 2079, lawyers had been abolished by execution. (TNG: "Encounter at Farpoint")
"Conservator" is the Cardassian equivalent of a lawyer. (DS9: "Tribunal")
After Kay Eaton disagreed with her husband Julius' idea on what to do with Benny Russell's Deep Space Nine story, Herbert Rossoff told her "You tell him, Kay. I know a good divorce lawyer if you need one". (DS9: "Far Beyond the Stars")
After he was arrested by Odo for smuggling kemacite, Quark told Rom to get him a lawyer. Rom suggested that he would contact Gaila for one. (DS9: "Little Green Men")
