adj. That can be vanquished; defeatable, conquerable.
the GNU version of the Collaborative International Dictionary of English
adj. That may be vanquished.
The Century Dictionary and Cyclopedia
Capable of being vanquished; conquerable; subduable.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. susceptible to being defeated
Word Usage
"But prejudices of taste, likings and dislikings, are not always vanquishable by reason; so, to escape the serenade from the tree, which promised to be of considerable duration"