Press cold youth resistant to change (8)

I believe the answer is:

ironclad

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'resistant to change' is the definition.
I can't judge whether this definition defines the answer.

'press cold youth' is the wordplay.
'press' becomes 'iron' (ironing is a kind of pressing).
'cold' becomes 'c' (eg on taps).
'youth' becomes 'lad' (I've seen this before).
'iron'+'c'+'lad'='IRONCLAD'

Can you help me to learn more?

(Other definitions for ironclad that I've seen before include "Absolutely determined" , "Old armoured warship" , "Well armoured - perhaps an alibi?" , "19th-century warship" , "monitor, for example" .)

I've seen this clue in The Telegraph.

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