The present article seeks to provide an answer to the following question: according to which mechanisms may a pattern of word formation develop a new meaning? In order to keep the task to a manageable size only changes will be considered, the result of which stays within the same type of pattern (affixation, compounding, etc.). Hence, we will not discuss how affixes develop out of compounds or similar phenomena. The only scholar who, to the best of my knowledge, has addressed this issue in a systematic and comprehensive manner is Jaberg (1905), who claimed that semantic change in affixation is always the result of semantic change in individual words plus reanalysis. Our study will reveal, however, that, though this is in fact the most common scenario, there is yet another, hitherto ignored mechanism of semantic change in word formation where no lexical change is involved. This mechanism, which will be called "approximation," allows a mismatch to arise between a word formation pattern and a neologism formed according to it, if the distance is bridged by metaphor or metonymy.