Sup*pos"a*bly

from The Collaborative International Dictionary of English v.0.48

Supposable \Sup*pos"a*ble\, a.
   Capable of being supposed, or imagined to exist; as, that is
   not a supposable case. -- {Sup*pos"a*ble*ness}, n. --
   {Sup*pos"a*bly}, adv.
   [1913 Webster]