adj. Not able to be held, as of an opinion or position; unholdable, indefensible.
The Century Dictionary and Cyclopedia
Not tenable; that cannot be held in possession: as, an untenable post or fort. That cannot be maintained by argument; not defensible: as, an untenable doctrine.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. (of theories etc) incapable of being defended or justified
Word Usage
"Moosa, on Wednesday to intervene in what it called the untenable situation of South Africa's conservation sector."