Well you're not committing the money to purchase an asset that will generate returns, so no, it's not "investing".
It would be more accurate to say you're working, really: spending time and effort to earn money. Though the "work" here, assuming you're a skilled poker player sitting with lesser-skilled marks, is similar to a crypto bro performing a rug pull. You're enabling other participants to gamble in the hope of an uncertain win, while they actually are pretty much guaranteed to lose in a zero-sum game where the house will always earn its keep.
One could say that if everybody else at the table is gambling and you're working, it's still gambling. Lunch is lunch, whether you're the customer, the chef, or the lamb.
In poker the asset I invest in is just very short term - a single hand. I put money in when I expect the asset of that hand to pay off, risking the money a bit like an even shorter term day trade.
I don't think this thread is the best place for the everlasting debate on whether day trading is "investing", but for the purposes of my definition above, day trading, like other kinds of trading like buying commodities for resale, or having a booth at the flea market, would fit my definition of "work" (you purchased something that you expect to generate profit from by putting in your time and effort) rather than investment, since the poker hand is not doing anything by itself to generate value/money/returns for you.
It would be more accurate to say you're working, really: spending time and effort to earn money. Though the "work" here, assuming you're a skilled poker player sitting with lesser-skilled marks, is similar to a crypto bro performing a rug pull. You're enabling other participants to gamble in the hope of an uncertain win, while they actually are pretty much guaranteed to lose in a zero-sum game where the house will always earn its keep.
One could say that if everybody else at the table is gambling and you're working, it's still gambling. Lunch is lunch, whether you're the customer, the chef, or the lamb.