incapable of being or occurring; not possible
seemingly incapable of being done, attained, or fulfilled; insuperably difficult
an impossible task
difficult to believe
an impossible story
extremely undesirable or difficult to put up with or deal with
Life became impossible because of lack of money
impossibility /-ʹbiliti/ noun
impossibly adv
[Middle English via French from Latin impossibilis, from in-1 + possibilis: see possible1]