The subject of this paper is the Russian adverb vporu ‘fitting’ in the language of the 19–20th centuries. In the 19th century the word vporu retained an association with the idea of time (cf. pora ‘time to do smth.’), and its semantics was more abstract. In the modern language the word vporu is still used in some of its “old” meanings in newspaper style, but in general this word belongs to the colloquial language and its “old” meanings have given way to semantically richer ones characterized by intricate modal frames. As a result, in contemporary Russian the word vporu can be combined with negation and certain other particles only with difficulty. The paper discusses changes in polysemy structure of the word and attempts to explicate various meanings of the word vporu in the language of the 19th century and today. The general issue of hierarchization of meanings of polysemantic words and their representation in a dictionary is also discussed.