A hyperbole is an exaggeration for emphasis or humour that beats you over the head with its meaning.
(Unless, like in the previous sentence, it’s been worn trite.)
Consider the following Quote taken from the first chapter of Ken Kesey’s One Flew Over the Cuckoo’s Nest (1962). It describes the Big Nurse, Mrs Ratched, preparing to punish three black orderlies in the mental institution where she works. The narrative is provided by Ol’ Chief “Broom” Bromden, a huge half Indian, who has been a Chronic patient on her ward since the Second World War.
Quote: She goes into a crouch and advances on where they’re trapped in a huddle at the end of the corridor. … She’s going to tear the black bastards limb from lib, she’s so furious. She’s swelling up, swells till her back’s splitting out the white uniform and she’s let her arms section out long enough to wrap around the three of them five, six times. … she really lets herself go and her painted smile twists, stretches to an open snarl, and she blows up bigger and bigger, big as a tractor, so big I can smell the machinery inside the way you smell a motor pulling too big a load.
Just when you think that’s it, you’re brought back to the image.
…all the patients start coming out of the dorms to check on what’s the hullabaloo, and she has to change back before she’s caught in the shape of her hideous real self.
After about two pages, you realise the language of the Quote is there to stay. The psychedelic descriptions, as well as, the motif of size—whether of the nurse, of the narrator, or of any other patient—repeat throughout the book.
What makes the Quote quiver?
Unapologetic, prolonged exaggeration.
It swings the mood between hallucinogenic and macabre, showing the reader both the insanity of mental illness and the insanity of the proposed cure.