Meaning : Something that cannot be done.
Example :
His assignment verged on the impossible.
Meaning : Not capable of occurring or being accomplished or dealt with.
Example :
An impossible dream.
An impossible situation.
Capable of happening or existing.
A breakthrough may be possible next year.Meaning : (used of persons or their behavior) not acceptable or reasonable.
Example :
Impossible behavior.
Synonyms : unacceptable