Undiscovered (6)
(Other definitions for latent that I've seen before include "Potential, dormant" , "Potential not realised" , "Existing but hidden" , "waiting to be discovered" , "Existing but not yet manifest" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">undiscovered</span>' is the definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for unknown that I've seen before include "Strange - obscure" , "Not familiar" , "Obscure, unheard-of, nameless" , "Anonymous" , "x, y or z, possibly" .)