ageist
adjective
[ ˈeɪdʒɪst ]
• characterized by or showing prejudice or discrimination on the grounds of a person's age.
• "a lot of ageist jokes about not being able to use technology"
ageist
noun
• a person with ageist views.
• "critics who contend that her age is an issue have been dismissed as ageists who are out of touch with the times"