Canoe bobbing on this? (5)
I believe the answer is:
ocean
'this?' is the definition.
The definition suggests a singular noun which matches the answer.
'canoe bobbing' is the wordplay.
'canoe' anagrams to 'OCEAN'.
However, I am not sure how the anagram is indicated.
'on' acts as a link.
(Other definitions for ocean that I've seen before include "Large body of salt water" , "A lot of water!" , "Great sea" , "Huge sea" , "Very large area of sea" .)