MorfFlex CZ 2.1 is the Czech morphological dictionary developed originally by Jan Hajič as a spelling checker and lemmatization dictionary. MorfFlex CZ 2.1 is a part of the PDT-C 2.0 release https://hdl.handle.net/11234/1-5813. It is a minor upgrade from MorfFlex CZ 2.0, with the tagset unchanged, but with some additions and corrections for full compatibility with PDT-C 2.0 morphological annotation.
MorfFlex is a flat list of lemma-tag-wordform triples. For each wordform, full inflectional information is coded in a positional tag. Wordforms are organized into entries (paradigm instances or paradigms in short) according to their formal morphological behavior. The paradigm (set of wordforms) is identified by a unique lemma. Apart from traditional morphological categories, the description also contains some semantic, stylistic and derivational information.
For more details see a comprehensive specification of the Czech morphological annotation https://ufal.mff.cuni.cz/techrep/tr64.pdf .