In Information Technology and specifically Computer Science, the term "Grey beard" or "Greybeard" is used as a droll, sarcastic way to describe any person who is older. Typically, a Grey Beard in IT will be very specific about methodology and have well-reasoned arguments about why the methods they are using are superior to current ideas and methods. Many times, they're not wrong!
A middle-aged man. Old enough to have some white (gray) hair, but not completely white yet. Graybeards tend to think of themselves as wise and experienced, while younger people just consider them "old."
Dude, I thought that graybeard would be humming Frank Sinatra, but when I walked by his office, he was jamming to Brother Ali!
An older man, usually someone with seniority in a business, a labor union or other community. Often used disrespectfully by younger members when referring to preferential treatment or out-dated behavior.