Eternally frustrating, 9 letters
Futile on a grand scale, 9 letters
Laborious and futile result of sin - he pays, rolling (9), 9 letters
Stone roller in Hades, 8 letters
(Greek legend) a king in ancient Greece who offended Zeus and whose punishment was to roll a huge boulder to the top of a steep hill, 8 letters
Each time the boulder neared the top it rolled back down and Sisyphus was forced to start again, 8 letters
An arthropod family of the order Neuroptera that includes spongeflies, 9 letters
Chiefly North American grasslike herbs, 12 letters