Wiktionary
vb. (context idiomatic English) To willingly accept the premise of a story or work of art for the sake of enjoying it.
Usage examples of "suspend one's disbelief".
The uppers were so deep in his skull that the roots were twined around the parts of his brain responsible for perceiving the color blue (on one side) and being able to suspend one's disbelief in bad movies (on the other) and between these teeth and actual air, light and saliva lay many strata of skin, meat, cartilage, major nerve-cables, brain-feeding arteries, bulging caches of lymph nodes, girders and trusses of bone, rich marrow that was working just fine thank you, a few glands whose functions were unsettlingly poorly understood, and many of the other things that made Randy Randy, all of them definitely falling into the category of sleeping dogs.
It was impossible to suspend one's disbelief---and what with the audience jeering and throwing peanuts, the whole thing was a disaster!
One must be able to suspend one's disbelief in ghoulies and ghosties and other denizens of the worlds of fantasy.