adj. 25B6; adjective
this view is insupportable : UNJUSTIFIABLE, indefensible, inexcusable, unwarrantable, unreasonable; baseless, groundless, unfounded, unsupported, unsubstantiated, unconfirmed, uncorroborated, invalid, untenable, implausible, weak, flawed, specious, defective.
the heat was insupportable : INTOLERABLE, insufferable, unbearable, unendurable; oppressive, overwhelming, overpowering, more than flesh and blood can stand; informal too much.
justified, bearable.