uncharted territory

Noun

uncharted territory (countable and uncountable, plural uncharted territories)

1. An area of land never before explored, mapped, or surveyed.

   Synonyms:

   terra incognita

   Antonyms:

   home ground, homeland

2. (figuratively) Ideas, concepts, or situations that have never yet been tried or explored.
   • Echoing the rhapsodic prog-rock vibes of Pink Floyd circa ‘Dark Side Of The Moon’, the new track marks an ambitious step into uncharted territory for Coldplay, though not eschewing too far from the alt-rockers’ standard fare.2021 July 23, Ellie Robinson, “Coldplay shoot for the stars with their cinematic new track ‘Coloratura’”, in NME
   • UN agency says El Niño and human-induced climate breakdown could combine to push temperatures into ‘uncharted territory’[.]2023 May 17, Fiona Harvey, “World likely to breach 1.5C climate threshold by 2027, scientists warn”, in The Guardian, →ISSN

   Synonyms:

   terra incognita, uncharted water