noun
rootless; without roots; groundless
Describes something lacking a foundation, basis, or origin; often used figuratively for people without a stable home or for unfounded rumors.
彼は根無し草のように世界中を旅している。
He travels the world like a rootless wanderer.
その噂は根無しだ。
That rumor is groundless.
A common compound meaning 'rootless grass' or a person without a fixed home; 根無し is the shorter, more abstract form.
Compound of 根 (root) + 無し (without). The exact historical derivation is uncertain, but the meaning is transparent.