Unsustainable(adjective)
That cannot be continued at the same level, rate, etc.
Hindi meaning:अस्थिर
Synonyms: Untenable, Indefensible, Unjustifiable, Unverifiable
Antonyms: Sustainable, Feasible, Tenable, Justifiable
Example: It's unsustainable above 80 degrees.
Trick to remember: Jo sustain na kr sake wo unsustainable hai. 
