Determined to be under canvas (6)
I believe the answer is:
intent
I believe this clue is a double definition.
'determined' is the first definition.
(I've seen this before)
'under canvas' is the second definition.
(I've seen this in other clues)
'to be' is the link.
(Other definitions for intent that I've seen before include "Resolved; purpose" , "set" , "Earnest, purpose" , "'Purpose, aim (6)'" , "Meaning -- determined" .)