Most likely not spoiled but probably won't taste as good. Instead of eating it straight from the jar you might work on blending it into other preparations, say like a remoulade or spread it on chicken breasts (or rabbit) before sauteeing them in sizzling oil with onions. Calves liver anyone?

Thanks all! Mustard goes with turkey, right? ;-)

it's fine...very acidic and nothing there to spoil

I'm with TiggyBee on this. Should be fine.

If it's unopened, I'm thinking it's good.

Does it have an expiration date on it? It could be ok--it's pretty acidic. I guess you could open one and look at it and smell it. And, you know, if in doubt...