Implausible(adjective)
Not seeming reasonable or likely to be true
Hindi meaning:अकल्पनीय
Synonyms: Unlikely, Improbable, Unbelievable, Doubtful
Antonyms: Plausible, Likely, Reasonable, Credible
Example: That is an entirely implausible plot development.
Trick to remember: Possible nhi hai implausible hai. 
