Source : Webster's Revised Unabridged Dictionary (1913)

Supportable \Sup*port"a*ble\, a. [Cf. F. supportable.]
   Capable of being supported, maintained, or endured;
   endurable. -- {Sup*port"a*ble*ness}, n. -- {Sup*port"a*bly},
   adv.

Source : WordNet®

supportable
     adj : capable of being borne though unpleasant; "sufferable
           punishment" [syn: {bearable}, {endurable}, {sufferable}]