Second, they broke down the wall between teen music and adult music, a wall that had been insuperable until then.
Not necessarily an insuperable or lethal problem, but a problem that must be overcome—and certainly not a plus.
But he prefers women - and most certainly does not love the baron, for the insuperable reason that he loves nobody except himself.
mid-14c., "unconquerable," from Latin insuperabilis "that cannot be passed over, unconquerable," from in- "not, opposite of" (see in- (1)) + superabilis "that may be overcome," from superare "to overcome," from superus "one that is above," from super "over" (see super-). Figurative use from 1650s. Related: Insuperably.