Cowardice
Etymology
From Old French "coart," from "coue" (tail), from Latin "cauda" — perhaps evoking a frightened animal with its tail between its legs, or one turning tail to flee. The tail-image is traditional, but the exact metaphor is uncertain.
noun · /KOW-ur-dis/
A failure of nerve — letting fear override what one ought to do.
What it names
Names not the feeling of fear but the surrender to it: the choice to shrink from duty or danger.
Example
Staying silent while a colleague was blamed for his mistake was an act of quiet cowardice.
Related idea
Fear is a feeling anyone may have; cowardice is fear allowed to govern action. Courage is not the absence of fear but the refusal to let it decide.