We’re moving next to the homophone: a word pronounced the same as another but differing in meaning, whether spelled the same way or not, as heir and air. So … contronyms are words that have contradictory meanings (sanctiion = approve and disapprove; homophones sound alike but to not mean the same—and often are not spelled the same, either.
cereal (noun): a breakfast food made from grain
serial (adj): arranged or happening in a series (noun): a story published or broadcast in separate parts over a period of time
He was a killer (serial)
Who found some fresh material
While watching movies (serial).
But then that kid from Cheerios
(The cereal—as each dude knows)
Pursued that killer (all such foes).
They had a fight imperial—
A deadly wound (arterial)—
And cereal beat serial!