The paper reports on an effort to reconsider the representation of some cases of derivational paradigm patterns in Bulgarian. The new treatment implemented within BulTreeBank-WordNet (BTB-WN), a wordnet for Bulgarian, is the grouping together of related words that have a common main meaning in the same synset while the nuances in sense are to be encoded within the synset as a modification functions over the main meaning. In this way, we can solve the following challenges: (1) to avoid the influence of English Wordnet (EWN) synset distinctions over Bulgarian that was a result from the translation of some of the synsets from Core WordNet; (2) to represent the common meaning of such derivation patterns just once and to improve the management of BTB-WN, and (3) to encode idiosyncratic usages locally to the corresponding synsets instead of introducing new semantic relations.