Important person taking old lady on river (7)
I believe the answer is:
grandee
'important person' is the definition.
'old lady on river' is the wordplay.
'old lady' becomes 'gran' (I've seen this before).
'on' says to put letters next to each other.
'river' becomes 'dee' (River Dee).
'gran'+'dee'='GRANDEE'
'taking' acts as a link.
(Other definitions for grandee that I've seen before include "Angered over Spanish noble" , "One of high rank" , "man of high rank abroad" , "A Spanish or Portuguese noble" , "VIP" .)