One of the motivations of the semantic transformation of the stable polylexical units (SPU) is the change of the sense of their components. Most SPU appear as a result of the sense change of free combinations of words, while the locutions come into being by way of conversion of free combinations of words into their stable, combinations, both on paradigmatic and syntagmatic axes. By the change of sense every semantic deviation is meant which leads to the loss by the SPU components of their own senses and to the appearance of new senses, realized only in a given unit. Although the SPU (especially phraseologisms) appear on the base of images, further at some later stages and under the influence of a series of linguistic factors, first of the semantic ones, they may lose there imaginative character. It is in such cases that the demotivation of an SPU takes place. This is the way the existence of both imaginative and not imaginative SPU is explained. A consequence of the sense change of the SPU components is the metaphorical transfer of components.