1. graded adjective & adjective Something that is weightless weighs nothing or seems to weigh nothing. ⇒ Photons have no mass–they are weightless. ⇒ ...weightless silk curtains. 2. adjective A person or object is weightless when they are in space and the earth's gravity does not affect them, so that they float around. ⇒ Helen described life in a weightless environment during her period in space. weightlessness
uncountable noun ⇒ ...the human body's response to weightlessness.
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