say it: in-sur-MOWN-tuh-buhl
insurmountable is an adjective meaning "not capable of being surmounted or overcome". It carries 2 recorded senses.
not capable of being surmounted or overcome
“insurmountable disadvantages”
impossible to surmount
Definitions, synonyms and semantic relations for insurmountable come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.