To initiate legal proceedings (against some person, group, or organization) in order to receive redress, reparation, or compensation. A noun or pronoun can be used between "sue" and "for" to indicated the person, group, or organization being sued. The employees have grouped together to sue for overtime that had not been paid since 2010. The family is suing the airline for $2.5 million to cover medical expenses, legal fees, and emotional damages.