I often use WordReference, which is quite good

Also, I recommend using Merriam-Webster, where you can find short definitions

As a traductor, you can use Deepl

I hope that I´ve helped you

I found one which I tested out with a few different words just to see how they explain them. I hope it is of some help. 

<a href="https://www.yourdictionary.com/">https://www.yourdictionary.com/</a>;