Well, you can say that you invest in equities, using the Kelly Criterion to ensure a viable capital investment. It's not far from the truth.
If they ask more about it, explain how 80% or more of the other investors in your market make too many wrong decisions which you are also able to profit from.
Finally tell them you play poker, and give them your winrate over 50k hands. Ask them to find you an investment advisor with the same record lol...
If you are a losing or leveling player, I would study a lot and become a consistent winner before telling some people.. some will never want to hear, and associate poker with degenerate gambling and mobsters (Joan Rivers for one) Just avoid the subject if possible.
My girlfriend is more bored than anything about poker - she's not so supportive as uninterested, but then she is more interested in what i can buy her with the winnings!
My mom is very proud of my acheivement so far - this from a mom who insisted I go to university etc.. values hard work and study. I studied very hard so far, and I think a fair bit of hard work. She was so excited about my recetn tourney cash and winnings, and understands that poker is a game of maths, psychology and skill - the top players win consistently.. This is so much different than many other types of gambling - especially the Lottery.