Inefficacious(adjective)
Not producing the desired effect.
Hindi meaning:बेअसर
Synonyms: Fruitless, Futile, Inefficient, Inexpedient, Useless
Antonyms: Effective, Efficacious, Efficient
Example: When the army’s strategy proved inefficacious, they switched tactics and incorporated guerrilla warfare.
Trick to remember: Efficiency kam hai to Inefficacious hai. 
