This work-in-progress paper presents the tool CZEDD which enables the user to learn how to predict the meaning of words. The CZEDD consists of (semi) automatic definitions for derived words because a lot of these words have predictable lexical meaning. The tool will be intended for foreigners who learn the Czech language and it could be useful as a dictionary and/or translator in which the definitions based on the word’s structure are stored. Two detailed case examples (the suffix