2. To have bodily pains which aren't that bad but make you feel old.
3. To feel old compared to the people in your life.
4. Staying inside and not going out, while regaling of your youthful days.
5. To look like an old man and/or feel like an old man.
2. After a summer of being a hermit, Jane had a serious case of old man syndrome.
Younger person: You mean according to Webster?
Old person: Yeah
Younger person: Well, this is Urban Dictionary!!! Its meant for fun if nothing else.
Old person: I got 20 years on you! You dont know what fun is!