General:
* Legal professional
* Legal scholar
* Legal practitioner
* Legal specialist
* Jurisconsult
* Jurist
* Attorney (this one is specific to those who can represent clients in court)
More specific:
* Lawyer (again, specific to those who can represent clients in court)
* Barrister (in some jurisdictions, a lawyer specializing in courtroom advocacy)
* Solicitor (in some jurisdictions, a lawyer specializing in legal advice and document drafting)
* Advocate
* Counsel
* Legal counsel
* Legal advisor
* Legal consultant
Formal:
* Distinguished legal mind
* Eminent jurist
* Leading authority on law
The best word to use will depend on the specific situation and the level of formality required.