Definition - Tennis - 4.5 and up Golf - single digit handicap. I chose the definition above, as these are around the levels where you can actually consider teaching others.... the average tennis teaching pro being around the 4.5s and in golf single digit handi means level3 certification for a assistant pro kind of position in a golf club. Also, above these levels, physical ability becomes a limiting factor for a not-so-athletic person like myself. It would take so much talent and work to achieve these levels, very difficult for those who don't do it full time..... I only know a couple of people... a friend of mine used to be a 4.5 and 8 handicap like decades ago... and a girl who's a 6.0 in tennis and now teaching golf full time in a local club.