Laughably derisive about right flower border (9)
I believe the answer is:
riverside
'laughably derisive about right' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'flower border' is the wordplay.
'flower' becomes 'river' (A river flows and is therefore a flower).
'border' becomes 'side' (I've seen this in other clues).
'river'+'side'='RIVERSIDE'
Can you help me to learn more?
(Other definitions for riverside that I've seen before include "Bank" , "Area along, say, the Thames" .)