What's the difference between "hardened" and "hardline"

[Curiosity2022]

Hello, Everyone on wordreference
Could you please tell me what is the different meanings between both "hardened" and "hardline"?

 

[Keith Bradford]

Hardened = mature from long experience.
Hardline = strict in observing party policy.

Which does Smith use?

 

[Curiosity2022]

Hardened = mature from long experience.
Hardline = strict in observing party policy.

Which does Smith use?

Well, He uses hardened, not hardline.

 

[PaulQ]

Public attitudes to the strike have hardened”,

That is the use of the verb "to harden" - to become inured to pleas; to become less flexible; to become polarized.

The adjective "hardened" is as Keith says, often in the sense of having heard all the counter arguments and dismissed them.