Cross river with idle vagrant (5)
I believe the answer is:
riled
'cross' is the definition.
(I've seen this before)
'river with idle vagrant' is the wordplay.
'river' becomes 'r' (abbreviation for river).
'with' means one lot of letters go next to another.
'vagrant' indicates anagramming the letters (I've seen this in other clues).
'idle' is an anagram of 'iled'.
'r'+'iled'='RILED'
(Other definitions for riled that I've seen before include "Annoyed" , "Vexed" , "get angry" , "Made angry" , "Irritated, provoked" .)