This article studies the interconnection between metaphor novelty and persuasiveness in communication, as well as contains a practical analysis of metaphor's perceived aptness and its relationship with metaphor novelty. Based on modern cognitive metaphor theory, this research contains a detailed analysis of the relationship between metaphor novelty and speech impact. Conventional metaphors, which are based on the categorization, contribute to a more clear and simple cognitive text perception. Thus, conventional metaphors reduce cognitive stress and improve the quality of perceived arguments. Novel metaphors, being based on comparison, have a predominantly affective effect, increasing the emotional appeal of speech and arousing the recipient's imagination. In addition, it was found that despite the fact that most scholars recognize the special role of novel metaphors in enhancing persuasiveness, the phenomenon of the metaphor perceived aptness plays an important role in this process. In the case when aptness is low, a novel metaphor can have a high emotional impact, but this will create the effect of cognitive rejection, which leads to a decrease in persuasiveness. To verify the relationship between perceived aptness and novelty, a practical study was conducted. This empirical research was aimed to analyze the perception of both conventional and novel conceptual metaphors with the WAR source domain. We analyzed the dependence in the perception of different types of metaphor on the content of the source domain (content variability) and the characteristics of the message recipients, namely, culture (cultural variability) and the professional or life experience (social variability). As a result of the study, it was found that the basic level of perceived aptness is the correspondence of the metaphor to the linguistic norm and linguistic experience of the speech message recipient. The perceived aptness of conventional metaphors is always higher than that of novel metaphors, but the specific meaning of perceived aptness depends on content and cultural variability. The life experience and professional orientation had a lesser effect on the level of perceived aptness. Thus, due to the fact that the perceived aptness directly depends on the context, genre, subject of the speech message and the specific language experience, knowledge and beliefs of the recipient of the speech message, this parameter is difficult to calculate, it can be determined only for each speech message in relation to a certain category of recipients and a certain type of culture.