Risk coming by river (9)
I believe the answer is:
adventure
'risk' is the definition.
(synonyms)
'coming by river' is the wordplay.
'coming' becomes 'advent' (advent is the arrival or coming of something).
'by' says to put letters next to each other.
'river' becomes 'ure' (river in Yorkshire).
'advent'+'ure'='ADVENTURE'
(Other definitions for adventure that I've seen before include "Exciting series of events" , "Dangerous undertaking" , "Exciting or daring experience" , "Hazardous operation" , "Risk" .)