antiearth adjective 2noun 2 adjective2 •Opposed to or destructive of the Earth and things native to the Earth.They see these manifestations of a patriarchal biased mentality as antifeminist, antihuman and antiearth. — 1995 •Facing or moving away from Earth.The Rx antenna has a single hinge line and during launch the reflector dish is restrained against the antiearth panel by two hold-down points. — 1985 noun2 •A hypothetical analog to Earth composed entirely of antimatter.This principle states that, if we could somehow replace every particle on earth with its antiparticle—thus creating a sort of antiearth—no one would be able to tell the difference. — 1958 •(historical) A hypothetical twin planet to Earth, proposed by the Pythagoreans, which cannot be seen from Earth.
