River boat's gone round, displaying flag (8)
I believe the answer is:
streamer
'flag' is the definition.
(I know that streamer is a type of flag)
'river boat's gone round' is the wordplay.
I cannot really understand how this works, but
'river' could be 'stream' (I've seen this in another clue) and 'stream' is found in the answer.
'boat' could be 'e' and 'e' is present in the answer.
A single letter 'r' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
'displaying' is the link.
Can you help me to learn more?
(Other definitions for streamer that I've seen before include "bold headline" , "Narrow decorative strip or flag" , "terrible cold?" , "Heavy cold" , "Long flag, tapering perhaps" .)