"Adamant" is a word in ENGLISH

adamant ENGLISH
Definition:

A stone imagined by some to be of impenetrable hardness; a
name given to the diamond and other substances of extreme hardness; but
in modern mineralogy it has no technical signification. It is now a
rhetorical or poetical name for the embodiment of impenetrable
hardness.

adamant ENGLISH
Definition:

Lodestone; magnet.

Few words of positivity

Kitai blinked slowly. "Why would you use the same word for these things? That is ridiculous.""We have a lot of words like that," Tavi said. "They can mean more than one thing.""That is stupid," Kitai said. "It is difficult enough to communicate without making it more complicated with words that mean more than one thing.

Jim Butcher, Academ's Fury

WORD SUGGESTIONS
Laugh your heart out.

Knock KnockWho's there !Becker !Becker who ?Becker the devil you know !

iron ENGLISH

Like iron in hardness, strength, impenetrability, power of endurance, insensibility, etc.;

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proof ENGLISH

The quality or state of having been proved or tried; firmness or hardness that resists impression, or does not yield …

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