innavigable

CIDE DICTIONARY

innavigable, a. [L. innavigabilis : cf. F. innavigable. See In- not, and Navigable.].

 Incapable of being navigated; impassable by ships or vessels.  [1913 Webster]

ROGET THESAURUS

innavigable

Impossibility

N impossibility, what cannot, what can never be, sour grapes, hopelessness, impossible, not possible, absurd, contrary to reason, unlikely, unreasonable, incredible, beyond the bounds of reason, beyond the bounds of possibility, beyond the realm of possibility, from which reason recoils, visionary, inconceivable, prodigious, unimaginable, inimaginable, unthinkable, impracticable unachievable, unfeasible, infeasible, insuperable, unsurmountable, insurmountable, unattainable, unobtainable, out of reach, out of the question, not to be had, not to be thought of, beyond control, desperate, incompatible, inaccessible, uncomeatable, impassable, impervious, innavigable, inextricable, self- contradictory, out of one's power, beyond one's power, beyond one's depth, beyond one's reach, beyond one's grasp, too much for, ultra crepidam, the grapes are sour, non possumus, non nostrum tantas componere lites, look for a needle in a haystack, chercher une aiguille dans une botte de foin, il a le mer +a boire.