yellowed

/Y EH1 L OW0 D/
verb
  1. 1

    To become yellow or more yellow.

  2. 2

    To make (something) yellow or more yellow.

adjective
  1. 1

    Having a yellow color (or discoloration), especially when due to age; having been made yellow.

Source: https://en.wiktionary.org/wiki/yellow, https://en.wiktionary.org/wiki/yellowed