Noun reliever has 3 senses
  1. stand-in, substitute, relief, reliever, backup, backup man, fill-in - someone who takes the place of another (as when things get dangerous or difficult); "the star had a stand-in for dangerous scenes"; "we need extra employees for summer fill-ins"
    --1 is a kind of peer, equal, match, compeer
    --1 has particulars:
     locum tenens, locum; double, stunt man, stunt woman; surrogate, alternate, replacement
    Derived form: verb relieve2
  2. reliever, allayer, comforter - a person who reduces the intensity (e.g., of fears) and calms and pacifies; "a reliever of anxiety"; "an allayer of fears"
    --2 is a kind of person, individual, someone, somebody, mortal, human, soul
    Derived form: verb relieve4
  3. reliever, relief pitcher, fireman - a pitcher who does not start the game
    --3 is a kind of pitcher, hurler, twirler
    --3 has particulars: closer, finisher
    Derived form: verb relieve2