Unfortunately, the answer is no. There are two reasons for this:
1. You cannot select parts of a word.
2. The Mobipocket word segmentation algorithm wasn't properly implemented in the Kindle code.
For example, if you look up "l’avait" in the default monolingual French Kindle dictionary you'll get the entry for "laver" instead of "avoir" because the Kindle app apparently treats all quotes as punctuation characters and deletes them before the string is passed to the dictionary lookup code.
Unfortunately, the actual Kindle behaves exactly in the same way, which is rather annoying, because Mobipocket Reader
on which the Kindle app is based doesn't have this problem.
If you want to use foreign language Mobipocket dictionaries with ebooks on the PC, I'd recommend using Mobipocket Reader instead, because it allows you to search multiple dictionaries and it'll find words such as "l’étoffe."