From puresso; inflamed, i.e. (by implication) feverish (as noun, fever) -- fever.
see GREEK puresso
1. fiery heat (Homer, Iliad 22, 31 (but interpreters now give it the sense of 'fever' in this passage; cf. Ebeling, Lex. Homer under the word; Schmidt, Syn., chapter 60 § 14)).
2. fever: Matthew 8:15; Marki. 31; Luke 4:39; John 4:52; Acts 28:8, (Hippocrates, Aristophanes, Plato, and following; Deuteronomy 28:22); πυρετῷ μεγάλῳ, Luke 4:38 (as Galen de diff. feb. 1, 1 says συνηθες τοῖς ἰατροῖς ὀνομάζειν ... τόν μέγαν τέ καί μικρόν πυρετον; (cf. Wetstein on Luke, the passage cited)).