The phrase "separate lawsuit" means a legal case that is independent and distinct from another lawsuit. It involves different parties or issues that are not related to the original case. Full definition
We had both been sued in separate lawsuits by the same corporation. (patrickconkeylaw.com)
Instead of starting separate lawsuits or having each plaintiff named in the case, the representative plaintiff can pursue the claim on behalf of the class. (torys.com)
In September, the men filed separate lawsuits against Long and his New Birth Missionary Baptist Church. (religion.blogs.cnn.com)