The first translation "fighter" (where Norwegians use the same term as the English - meaning he/she has a fighting spirit, is not willing to give up easily when ill or in a difficult situation (as in a "the survival of the fittest"-meaning.
"Gjenlevende" means a person left following the death of someone close to that person, i.e. husband,wife. The newt two terms: "etterlatt" and "lengstlevende" are used mainly in legal language.