tricky

Something that's tricky is difficult or hard to do because it requires careful thought and attention. It might also be sneaky or clever in a way that's not entirely trustworthy.

When we say something is tricky, we usually mean that it has some kind of catch or complication that makes it hard to understand or accomplish. For example, you might think a puzzle game is tricky if the clues are hidden or the rules aren't clear. Or, your teacher might say that a math problem is tricky because it involves some complicated formulas. Sometimes "tricky" can also imply something is sneaky or underhanded, like a salesperson using manipulative tactics to make you buy their product.