reliever

/R IY0 L IY1 V ER0/
noun
  1. 1

    Something which relieves (pain, etc.).

  2. 2

    A relief pitcher.

    โ€œThe first reliever got the last two outs of the sixth.โ€

  3. 3

    Someone who fills in for another.

    โ€œI'll be the reliever today so that you can each take a break.โ€

  4. 4

    A garment kept for being lent out.

Source: https://en.wiktionary.org/wiki/reliever