Waters in which canoes get upset (6)
I believe the answer is:
oceans
'waters' is the definition.
(ocean is a kind of water)
'canoes get upset' is the wordplay.
'get upset' indicates an anagram (I've seen 'getting upset' mean this).
'canoes' is an anagram of 'OCEANS'.
'in which' is the link.
(Other definitions for oceans that I've seen before include "Large bodies of water" , "Vast bodies of water" , "Atlantic, Pacific etc" , "Great seas" , "Arctic and Indian" .)