Delayed, having attempted to cross a river (7)
I believe the answer is:
tarried
'delayed' is the definition.
(I've seen this before)
'attempted to cross a river' is the wordplay.
'attempted' becomes 'tried' ('try' can be a synonym of 'attempt').
'to cross' indicates putting letters inside (some letters cross or go round others).
'river' becomes 'r' (abbreviation for river).
'a'+'r'='ar'
'tried' going around 'ar' is 'TARRIED'.
'having' is the link.
(Other definitions for tarried that I've seen before include "Lingered, being tardier" , "Stayed longer than intended" , "Delayed in coming or going" , "Loitered" , "as 13 [LAGGARD] may have" .)