Wordmap should certainly be useful to those who choose to download it. The developer must be congratulated on his skill.
But purchasers should be aware that it is obviously a blatant copy of Wordflex Touch Dictionary which has been around for six years. There's a free version to try that's limited not in scope, but by the number of words you can check in a day, and a paid upgrade to the full version.
Wordflex has the advantage of a much larger database of words based on three Oxford University Press publications: the Oxford Dictionary of English, the foremost single-volume dictionary of the language with 355,000 words and phrases, the New Oxford American Dictionary, which is comparable in extent, and the Oxford Thesaurus of English. (It also has some special features not duplicated by InteractiveThesaurus.)
I have used Wordflex for five years in my work as a writer and editor. I highly recommend it to serious students of, and workers with, the English language.