A problem that is insuperable cannot be dealt with successfully. an insuperable obstacle to negotiations. = insurmountable. an insuperable difficulty or problem is impossible to deal with (from superare , from super )
[ (")in-'sü-p(&-)r& ] (adjective.) 14th century. Middle English, from Middle French & Latin; Middle French, from Latin insuperabilis, from in- + superare to surmount, from super over; more at OVER.