Also found in: Wikipedia.
A situation or circumstance that is foreign, unclear, or uncharted and which may be dangerous or difficult as a result. We're starting to get into uncharted territory exploiting these tax loopholes. If we aren't careful, the government may crack down on us hard! John has always kept himself closed off from family members, so his real feelings have been uncharted territory for all of us.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.