The aim of this study was to explore the concept acute semantically. The concept is being used both in clinical and theoretical contexts, without questioning whether a clear meaning of the concept has been established. The analysis has been applied according to the semantic analysis strategy of the philosopher (and pedagogue) Koort (1975). First, the results show that the concept of acute has had an unclear meaning and perception in the Norwegian language. Second, the synonyms indicate two different contents. The experiences and events that occur acute might be experienced as 'sharp' and 'intense'. The synonyms point also at time, such as quick, rapid and swift. Third, it reveals that the shortlived experience as synonym does have a very little binding to the concept acute. The occurence that began suddenly is not meant to subside the same way as it began.