the GNU version of the Collaborative International Dictionary of English
adj. Without a chart; having no guide.
adj. Not mapped; uncharted; vague.
The Century Dictionary and Cyclopedia
Not charted, or not provided with a chart; hence, without a guide or guidance: as, a chartless rover.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. (of unknown regions) not yet surveyed or investigated
Word Usage
"Already, over unknown trails and chartless wildernesses, were the harbingers of the steel arriving, -- fair-faced, blue-eyed, indomitable men, incarnations of the unrest of their race."