im·pal·pa·ble
adjective/ɪmˈpælpəbl/
/ɪmˈpælpəbl/
(formal)- that cannot be felt physically
触摸不到的;感觉不着的 - very difficult to understand
opposite palpable难以理解的;难懂的
Word Originearly 16th cent.: from French, or from late Latin impalpabilis, from in- ‘not’ + palpabilis, from Latin palpare ‘feel, touch gently’.