As a noun:
* Despite their best efforts, the rescue team realized the futility of searching for survivors in the wreckage. (This sentence emphasizes the hopelessness of the situation.)
* The feeling of futility overwhelmed her as she watched the endless stream of cars on the highway, each one carrying a life she could never touch. (This sentence highlights the feeling of pointlessness.)
* After years of trying to convince her parents, she finally accepted the futility of her argument. (This sentence focuses on the lack of success in an attempt.)
As an adjective:
* The doctor's prognosis was a stark reminder of the futility of modern medicine in the face of this rare disease. (This sentence emphasizes the pointlessness of medical intervention.)
* Her efforts to reach him were futile; he had already left the country. (This sentence shows that her actions had no effect.)
* The endless paperwork felt like a futile exercise, accomplishing nothing but adding to the already overwhelming workload. (This sentence highlights the pointlessness of the task.)
These examples demonstrate how "futility" can be used in various contexts to convey the sense of hopelessness, pointlessness, or lack of success.