the.com/sleeping giant

means A person, group, or thing with great untapped power or potential that hasn't yet been activated or provoked.

from Not a word with a single coinage but a standing metaphor, built from two plain words — 'sleeping' and 'giant' — stacked together for effect. The image draws on old folklore and legend, where giants are enormous beings whose strength is terrifying precisely because it's dormant: think of giants in fairy tales who slumber for ages, harmless until woken. The phrase got especially popular in military and political speech, famously (if apocryphally) attributed to a Japanese admiral warning that attacking Pearl Harbor would 'awaken a sleeping giant' — a line likely invented later for a film, not spoken at the time, but it cemented the phrase in modern usage. From there it spread into sports, business, and politics to describe any underused power waiting for its moment.