Lacking grit; without determination, courage, or perseverance; also lacking graininess or sandy texture.
From 'grit' with the negating suffix '-less,' meaning the absence of either physical grit (sand) or metaphorical grit (courage).
The metaphorical use of 'gritless' to mean spineless comes from the 1800s—people admired 'gritty' pioneers, so calling someone gritless was the ultimate insult to their character.
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