It seems that your English is good enough that you'd benefit from an English/English dictionary instead of relying on a German/English dictionary. That way, you're understanding the meaning in the same context as native speakers and without being tainted by connotations of words used in the German definition. (I have this problem all the time with English/Japanese dictionaries; I look something up and it doesn't make sense. Then I look it up in a Japanese/Japanese dictionary and everything makes perfect sense. Of course, sometimes that requires a few more trips to the dictionary to understand the definition, but...)
Anyway, if I were learning English I'd pay the $300 for an Oxford English Dictionary. You'll learn a lot that way.