dispensable

Short definition from Wiktionary

Adjective

1. 1
   Able to be done without; easily replaced.
2. 2
   Capable of being dispensed.
3. 3
   Subject to dispensation; possible to relax, exempt from, or annul.
4. 4
   Not essential to be taken in as part of an organism's diet, as it can be synthesized de novo.

Noun

1. 1
   Something that can reasonably be dispensed with; something unnecessary.