Sea in which canoe collapsed? (5)
I believe the answer is:
ocean
'sea' is the definition.
(synonyms)
'canoe collapsed?' is the wordplay.
'collapsed?' indicates anagramming the letters.
'canoe' with letters rearranged gives 'OCEAN'.
'in which' acts as a link.
(Other definitions for ocean that I've seen before include "Pacific, perhaps" , "Big sea" , "It's pretty wet!" , "Great sea" , "eg Indian, Atlantic" .)