Does it still smell of turmeric… or more like cardboard? Many herbs & spices don't 'go off' so much as eventually taste & smell of almost nothing.
Heat a couple of tablespoons of oil, drop half a teaspoon of turmeric into it. Stir briefly. Don't burn it.
Can you smell it properly?
Pour out & let it cool.
Once cooled try dipping some plain white bread into it & tasting.
Does it still taste of anything?
My guess would be it's now little more than yellow powder. Great as a dye, not so much as a spice.
I'd think its saving grace, if there still is one after all this time, is that you bought it close to source. Supermarket spices can be as dead when you first open them as good ones at 2 years.
2 years is really about as far as I'd ever try to stretch though. 10 is more than pushing it.