Reliever

Noun

1. Something which relieves (pain, etc.).

   "Pepto-Bismol is an upset-stomach reliever."

2. A relief pitcher.

   "The first reliever got the last two outs of the sixth."

3. Someone who fills in for another.

   "I'll be the reliever today so that you can each take a break."

4. A garment kept for being lent out.