Has definitions, synonyms, localismos, works both ways (can type in either language). Has verbs conjugation, showing the irregular verbs in red, which is incredibly handy. (I wrote them a letter two weeks ago asking for that same feature and voila, here it is). One can re-arrange the order of the tenses to his own liking or remove those he doesnt need. Displays also phrases, proverbs, sayings with definitions for the whole thing. Can group the favorites in folders - extremely handy for building vocabulary in a more systematic way. Very few other dictionaries have that feature.
All that said, there are things that can be improved, like theres no example phrases, there are "quotables" (in-app purchase) but they are often quite off, sometimes dont even contain the word and in general Id say useless. And in general the whole lineup of WordMagic dictionaries could do with some clarification on what is the difference between the editions costing twice & triple this one. At this price point, I think the customer should be better informed.