I still have my old copy of the Hans Wehr Arabic/English dictionary from my university days and I still find it very useful when looking up the odd word. But its very tatty and split in two and some pages are missing lol.
Then I remembered that one of the wonders of the age we live in is that there are apps for almost anything - and since I have a nice new smartphone I thought I check it out - and YES, some guy scanned every page and made it searchable!!
So if you want what is still one of the best Arabic/English dictionaries available - FREE - then go to your app store and download "Arabic Almanac" (Not sure why it's called that?)
https://play.google.com/store/apps/details?id=com.etjaal.arabicalmanac&hl=enLisan al-'Arab is also available:
https://play.google.com/store/apps/details?id=com.nujoomapps.lesan.trial&hl=enanother good dictionary that I bought many years ago in Egypt is al-Mu'jim al-Wasit and yes it's been made into an app too:
https://play.google.com/store/apps/details?id=com.nujoomapps.waseet.trial&hl=enThe last two above are Arabic only - but if you want a simple but very good Arabic-English AND English-Arabic dictionary, that has been made in to a really excellent app - easier to use than all the above, very flexible, neat and well designed - then al-Mawrid is your boy:
https://play.google.com/store/apps/details?id=com.baidu.dict.arabic&hl=en 