This paper deals with the semantic phenomenon of lexical polysemy. The theoretical part covers mostly the topic of polysemy. It illustrates the difference between polysemy and the phenomenon of homonymy and vagueness. It also defines metaphor and metonymy from cognitive linguistics’ point of view, which play a great role in meaning extension. The research is based on the analysis of 59 examples in English and 44 examples in Croatian. The aim of the paper is to explore the extent and the limits of polysemy of the adjective hot in English, and of its Croatian counterpart vruć, as well as the role of metaphor and metonymy in meaning extension of the adjective hot, i.e. vruć. The analysis discusses the translations of the adjective hot to Croatian, and vice versa, the translations of the Croatian adjective vruć to English. The results show that meaning extensions are mostly defined by means of metaphor and metonymy. Considering the contrastive analysis between the English adjective hard and its counterparts in Croatian, and the tolerance in terms of polysemy, the results make English more polysemy-friendly than Croatian.