An attorney recently referred to me as a "Stripper" in an email between lawyers. This is false. Is a libel case possible?

The publishing of false facts is the foundation of defamation. An action for defamation requires: (1) a false and defamatory statement; (2) an unprivileged publication to a third person; (3) fault, amounting to at least negligence; and (4) actual or presumed damages. The first element is often the hardest to prove, which is that the statement was a false statement of fact. Truth is a defense to defamation. The second issue is that (except in a few limited cases) you are required to show damages, which means some loss which you have suffered as a result of these lies. If your attorney was the recipient of the email (and presumably knows the falsity of the representation) there likely are no damages.   However you may have a claim against the attorney for unprofessional conduct under the Rules of Professional Conduct.