It's called WordHippo.
I'm currently doing a massive amount of editing for development agencies, we cover lots of subject from gender-base violence through to undertaking aid work in conflict-affected areas and, most recently, making money transfers to regions where there are no banks.
That's how I stumbled across WordHippo. I was looking for the plural of hawala, which I was fairly sure was hawala, but someone kept typing hawalas.
I was surprised to find the answer so easily. Not only did WordHippo give me the plural straight away, it told me where the word originated from and even told me how to pronounce it!
The site hadn't come up for me before, so I assume it's a new one or maybe I'm just late to the party, but I love it.