The best Arabic-English lexicon is Lane's Arabic-English Lexicon
Here is a link to 5,100 articles, by root, done by Edward Lane.
Each "root" has its own article, and its own PDF file.
Here is the link to the lexicon :
Lane's Arabic-Engish Lexicon
SPECIAL NOTE FOR ONLY MAC USERS :
These are PDF files, which are not supported in the browser on a Mac.
So the only way to view it is to download the individual PDFs.