No matter which language you are learning, having a good dictionary is always helpful. I am not going to endorse any dictionaries on the commercial market here but want to introduce to you a free dictionary that you could use online!
I am one of the 60+ worldwide volunteer editors of “The CantoDict Project”, a collaborative online Cantonese-Mandarin-English dictionary started in 2003. Even though the website advertises the project as a resource for students learning Cantonese or Chinese, I think it is also useful for learning English as well! Here is the link to the dictionary.
In regards to concerns about accuracy, as editors, we continuously check each other’s work and make modifications when necessary. We also welcome any feedback, suggestions, and comments in the forum. In fact, the forum also has many topics which may interest you! Parents could exchange child-rearing advice, those with technical computer skills could share expertise, cooking aficionados could exchange recipes, and movie buffs could critique the latest movies. Thus, it is a great platform to practice writing English! Besides the dictionary and a forum, there is also a parser.
Whether you are learning English, Cantonese, or Mandarin, hopefully you’ll find some aspect of this online dictionary useful!