Synonyms for impossible

modified

1. Incapable of being considered

   inconceivable, unthinkable, vain, hopeless, infeasible, unachievable, unattainable, out of the question, insurmountable, useless, impassable, inaccessible, unworkable, preposterous, absurd, illogical, incredible, untenable, implausible, unimaginable, unobtainable, not to be thought of, hardly possible, beyond the bounds of possibility, like finding a needle in a haystack*, a hundred to one*; see also futile 1, hopeless 2.

   Antonyms possible*, likely, reasonable.

2. Having little likelihood of accomplishment

   improbable, unlikely, impracticable, too much for; see difficult 1, 2.

3. Undesirable; said of things

   unacceptable, improper, objectionable, incongruous; see offensive 2, undesirable, unsuitable.

4. Disagreeable; said of persons

   difficult, unmanageable, hard to deal with; see irritable, obstinate, undesirable.