Both Uses

malleable
in
The House of the Seven Gables
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The mistress of the house, meanwhile, as is usual with persons of her stiff and unmalleable cast, stood mostly aside; willing to lend her aid, yet conscious that her natural inaptitude would be likely to impede the business in hand.†
Chpt 5

unmalleable = not easily shaped or influenced

standard prefix: The prefix "un-" in unmalleable means not and reverses the meaning of malleable. This is the same pattern you see in words like unhappy, unknown, and unlucky.
The quality of Hepzibah's mind was too unmalleable to take new impressions so readily as Clifford's.†
Chpt 17 *

Definitions:

(1) (malleable)
of people: flexible or easily influenced

of materials: capable of being shaped or bent or drawn out
(2) (meaning too rare to warrant focus)