mardröm

Noun

 * 1) a nightmare (distressing, often frightening dream)
 * 2)  a nightmare (very bad situation or experience)
 * 1)  a nightmare (very bad situation or experience)
 * 1)  a nightmare (very bad situation or experience)

Usage notes
Both "dream [drömma] a nightmare" and "have [ha] a nightmare" are idiomatic in Swedish, emphasizing either the dreaming or the having.