Unlikely to agree but continues to cast about (11)

I believe the answer is:

contentious

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'unlikely' is the definition.
Both the definition and answer are adjectives. Maybe you can see a link between them that I can't see?

'agree but continues to cast about' is the wordplay.
'continues to' anagrams to 'CONTENTIOUS'.
But, I am unsure how the anagram is indicated.

'to' is the link.

Can you help me to learn more?

(Other definitions for contentious that I've seen before include "debatable" , "controversial" , "Likely to cause disagreement" , "Likely to cause an argument" .)

I've seen this clue in The Globe and Mail.

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