earth-shaking

The compound "earth-shaking" is a modern English formation built from two native Germanic elements. The literal image is of an event so powerful it causes the very ground to tremble, as in an earthquake. This vivid physical metaphor was then semantically extended to describe not geological events, but figurative ones—ideas, discoveries, or news—that are so profoundly impactful they seem to destabilize the established order or common understanding. Thus, the word's logic moves from a concrete, physical description to an abstract, intensive adjective denoting supreme importance or revolutionary effect.

Structure: earth (ground) + shaking (trembling) - earth: From Old English 'eorþe' (ground, soil, land). In this compound, it signifies the physical world or foundation. - shaking: From Old English 'sceacan' (to shake, move to and fro). The present participle form '-ing' functions as an adjective-forming suffix, indicating the action or state of shaking.