ageist

Adjective

 * 1) Unfairly discriminatory against someone based on their age.
 * Upon hearing that his employer would soon require yearly physical examinations and vision screening, my father exclaimed that the policy was ageist.
 * Even though she had succeeded in the phone interview, when the ageist employer learned that the candidate was only 18 years old, she became hesitant.

Noun

 * 1) A person who behaves in an ageist manner.
 * He didn’t like to think of himself as an ageist, but he had to admit that he hadn’t considered the needs of some of the more elderly participants.