"Flower": hard for audience to spot this means a body of water (5,3)
I believe the answer is:
irish sea
'this means a body of water' is the definition.
The definition suggests a singular noun which matches the answer.
'flower hard for audience to spot' is the wordplay.
'flower' becomes 'iris' (iris is a type of flower).
'hard' becomes 'h' (abbreviation used in pencil classifications).
'for audience' shows a homophone (sound like) (how it might sound to an audience).
'to spot' becomes 'see' (both can mean to notice or observe).
'see' sounds like 'sea'.
'iris'+'h'+'sea'='IRISH SEA'
Can you help me to learn more?
(Other definitions for irish sea that I've seen before include "Man's found here" , "Man located here" , "Isle of Man location" , "Large quantity of water" , "Man's situation" .)