Other forms: quicksands
Quicksand is wet loose sand that swallows whatever steps on it. Sink in quicksand, a patch of quicksand, caught in quicksand.
Films get it wrong: it is denser than a person, so you cannot sink over your head — the danger is being stuck as the tide comes in. Struggling makes it grip harder; leaning back and moving slowly works. The quick here means living, as in the quick and the dead.
1nounquicksandWet loose sand that gives way underfoot.
“The horse got stuck in quicksand and had to be pulled out with ropes.”
quicksand is ground.
Old English cwecesand is quick, in the old sense of living or moving, plus sand. The same quick survives in quicksilver.
Old English
cwecesand — quicksand
Middle English
quyksande
English, today
quicksand
From Middle English quyksande, from Old English cwecesand (“quicksand”), equivalent to quick + sand. Cognate with Swedish kvicksand (“quicksand”), Icelandic kviksandur, kviksyndi (“quicksand”). More at quick, sand.
Etymology from Wiktionary, CC BY-SA