unattainable (adjective)

1. The artist's vision of a perfect utopia was depicted in a painting, but it remained unattainable in reality.

2. The extravagant haute couture gown showcased on the runway was beautiful but completely unattainable for most people.

3. The protagonist's dream of finding true love and eternal happiness proved to be unattainable as the story unfolded.

4. Why did the math book become a stand-up comedian? Because it felt unattainable to solve all those problems!