Synonyms for impossible

Noun

1. impossible, impossibility, impossible action

usage: something that cannot be done; "his assignment verged on the impossible"

Adjective

1. impossible (vs. possible), hopeless, impracticable, infeasible, unfeasible, unworkable, out(predicate), unachievable, unattainable, undoable, unrealizable, hopeless, impractical, insurmountable#1, unsurmountable, unrealistic, unthinkable

usage: not capable of occurring or being accomplished or dealt with; "an impossible dream"; "an impossible situation"

2. impossible, inconceivable, out of the question, unimaginable, unthinkable (vs. thinkable)

usage: totally unlikely

3. impossible, insufferable, unacceptable, unsufferable, intolerable (vs. tolerable)

usage: used of persons or their behavior; "impossible behavior"; "insufferable insolence"