The "free" version of the app just doesnt have a comprehensive enough dictionary. I tried to use it while reading a French novel, and 2 out of every 3 words I looked up werent in the free dictionary. The most common words are, but then, those arent the words you look up, are they? Weird interface as well - when you look up a word, it gives you possible matches in both languages - why? Surely you only want to see French when youre looking up a French word?
KirkWO about French Translator Dictionary +, v6.2.71