Stubborn fellow? I'd heard otherwise (7)

I believe the answer is:

diehard

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'stubborn fellow?' is the definition.
The answer and definition can be both people as well as being singular nouns.
Maybe you can see a link between them that I can't see?

'i'd heard otherwise' is the wordplay.
'otherwise' is an anagram indicator.
'id'+'heard'='idheard'
'idheard' anagrammed gives 'DIEHARD'.

Can you help me to learn more?

(Other definitions for diehard that I've seen before include "Backer of a losing cause" , "traditionalist" , "Person who resists change" , "One to resist change" , "Obstinately conservative" .)

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

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