In the Russian proverb Utro vechera mudrenee (The morning is wiser than the evening) ‘it is better to postpone a complicated issue until the morning: the morning decision will be more reasonable’ the meaning of the whole phrase contradicts the modern meaning of the word mudrenyi ‘difficult to understand, perform, etc.; complex’. Meanwhile, the word mudrenyi has the meaning ‘clever, reasonable, quick-witted’ in folk dialects and historical dictionaries. In this meaning the word mudrenyi is often used in Russian folk tales. The word mudrenyi has the meaning ‘associated with the manifestation of reason, prudence, wisdom; wise, reasonable’ in the “Dictionary of the Russian language of the XI–XVII centuries” and the “Dictionary of the Russian language of the XVIII century”. These dictionaries put the word in line with the proverb Utro vechera mudrenee. In the XVIII century, the meaning ‘wise, clever’ became colloquial, while the meaning ‘complex, difficult’ remained stylistically neutral. In the XX century, the standard language no longer used the original meaning of the word mudrenyi fixed in the proverb, but dialects preserved it. This led to a conflict between the meaning of the proverb and the secondary meaning of the word mudrenyi which contradicted the meaning of the proverb. If we treat the verbal adjective as a folk analogue of a Church Slavonic passive participle similar to the pairs varit' (to boil) – varenyi (boiled), darit' (to give) – darenyi (given) and mudrit' (act wisely) – mudrenyi (done wisely; wise), the primary meaning of the word mudrenyi is derived from the meaning of the verb mudrit' ‘to think about the solution of some complex problems, tasks, to look for a way to do some work’ in the system of the modern Russian standard language.