Since there is speculation involved, many compare trading to gambling. But that isn’t the case as trading and gambling are two different things. Trading requires preparation and market analysis, which is certainly not what they do when they gamble.
It depends on the type of gambling. If you study the odds and know the type of gambling, it is more similar to trading. And in some specific games like poker or sports betting, where you can make EV+ bets, it would be even more similar.
If you play roulette while drinking a few drinks to pass the time, no, it is not similar to trading.