EN
The article discusses the causes of the disappearance of the association of derivatives with a derivational base visible during diachronic and etymological research. These may include the following: — disappearance or asubstantial change of the form of the word which is the basis for derivation; — change of the meaning of the derivational base or the derivative; — disappearance of the productivity of certain word-formative mechanisms (e.g. apophony); — disappearance of certain word-formative means, e.g. prefixes, which causes the word that arises by this means to be interpreted as anon-compound word; — obliteration of the original structure by phonetic changes which occur at the junction of morphemes; — change of realia. The particular causes of the changes are illustrated by examples derived from the Polish language.