A party or attorney who brings a civil claim that is not supported by probable cause (at least a 50% chance of success on the merits) commits the tort
of malicious prosecution
/wrongful institution of civil proceedings.
If that's what you are arguing has occurred, it's different from defamation. Defamation requires only a false statement of fact. A civil action
may have many statements which are ultimately proven false -- but when the statements are alleged, the attorney has a duty to conduct a good faith investigation sufficient to demonstrate that the case is "colorable" (meritorious) -- and not utter rubbish. If the attorney does so, then the client and the attorney are immune, because they have met the requirements necessary to avoid a malicious prosecution charge.
BotXXXXX XXXXXne, if you believe that the other party has pleaded a claim against you that is absolutely without merit, and a reasonable investigation by opposing counsel would demonstrate this, then you may have a malicious prosecution claim against the other party.
Of course there are other elements to malicious prosecution: (1) a criminal or civil judicial proceeding has been commenced against a defendant; (2) the proceeding was instigated by plaintiff; (3) the proceeding ended in favor of defendant; (4) the proceeding was instigated with malice; (5) without probable cause; and (6) resulted in damage to defendant." Kalt v. Dollar Rent-A-Car, 422 So.2d 1031 (1982).
If you can prove all of the above, then you have a case. Otherwise, I believe you cannot prevail.
Hope this helps.