Leave floating on the river for show (6)
I believe the answer is:
reveal
'show' is the definition.
(synonyms)
'leave floating on the river' is the wordplay.
'floating' indicates an anagram (float can mean fluctuate or oscillate).
'on' means one lot of letters goes inside another (as in clothing \'on\' a person).
'the river' becomes 'r' ().
'leave' anagrammed gives 'eveal'.
'eveal' placed around 'r' is 'REVEAL'.
'for' is the link.
(Other definitions for reveal that I've seen before include "Divulge; make visible" , "Make known to others" , "Make known, expose" , "Disclose or uncover" , "Make known or visible" .)