As Salaam 'Alaykum dear brothers and sisters,
A great website I have been using for some time now to increase my Arabic vocabulary has been
www.aratools.com
It is a very detailed website that shows you the root and grammatical meaning of the word you are looking for, as well as other possibilities if short vowels are not given in the word. When trying to understand the Qur'an, this website helps. It isn't the best tool, but it helps if you can't find a word in a dictionary and you want it right away. It certainly works better than google translate which gives only nonsense.
I suggest anyone who is eager to try and learn Arabic to use this because it has helped me a lot so far. Nothing compares to having proper lessons from a teacher of Arabic and receiving proper explanations for words, but this site is a good starter. You can learn from here, then proceed to a Shaykh or any scholar in Arabic, and find out more with precise questions.
It would be great if anyone else knows better websites to share that as well. It would help me out and others as well. Jazakallah.