futile

1 - In the end, scientists came to a conclusion that all the efforts had gone futile after considering the side-effects of the pills.

2 - Multiple expeditions to recover the ships and the remains of the crew proved futile.

3 - After years of negotiations, it appears that the entire process has been futile.

4 - Attempts to halt the fire with a fire extinquisher were futile.

5 - Surfing the net in a futile search for knowledge or enlightenment would silly.