What is Claimant ?
Claimant is (noun) 1. a person who claims something Benefit claimants will be paid late because of the bank holiday. 2. a person who starts a legal action against someone in the civil courts She’s the claimant in a libel action. The court decided in favour of the claimant. (NOTE: The former term was plaintiff. The other party in an action is the defendant.)
source: Easier English, Student Dictionary Upper Intermediate Level