This article examines the use of fuck and fucking in Danish, with a focus on their interactional functions for assessing. Data consist of 76 cases found in informal Danish conversations, analyzed within the framework of Interactional Linguistics. Fuck functions as a reactive interjection that prefaces various types of clauses. However, fuck followed by a copula clause develops an assessment out of a telling. Followed by hvor ‘how’ and an adjective, fuck performs agreeing assessment. Hvad fuck ‘what the fuck’ may occur in questions. Fucking is commonly used in copula clause assessments but also within noun phrases when no response is elicited. The study concludes that the use of fuck and fucking in Danish differs from their use in English, but also from the Danish swearword fanden ‘the devil, damn’. The conclusions indicate that interactional functions and constructions are an important factor for understanding the pragmatics of borrowing and swearing.