I've been a golf pro since the mid 1960s and one of my jobs as an assistant early in my career my boss was Big Pro and I was Little Pro. For two reasons, he was the boss and I was his assistant and he was 6'4" small forward and I was 5"11" point guard. Many of my old friends from back then still call me Little Pro. Some have shortened it to Pro.
Today I'm semi-retired and not so much acting as a golf pro as I am a clubfitting pro, and I am old. I'm a bit of a mentor for many clubfitters around the world. I've achieved Master of Gold Club Technology Status and been selected by Golf Digest as one of America's best clubfitters and Little Pro doesn't quite fit my image any more and some of the refer to me as "The Old Pro" from time to time.