(antonym means the opposite of course) "to dislike" is probably the best one "to spurn" would work as an antonym in certain situations.
An approximate antonym for prefer is dislike, or reject.
They prefer other sports.
The dislike in flavor;distaste.
Word that mean the opposite of fancy include plain, simple, common, drab, or unadorned. (the colloquial verb 'to fancy' - to like or prefer - would have the antonyms dislike, abhor, or hate)
dislike
to like or preferLike, liking, approval and love...
Animosity, dislike, or hate. Those words are the opposite of love.
A dislike of something or someone. It would be the opposite of sympathy.
It must be heterophobic.
Dislike intensely means loathe or detest or hate, but is a euphemistic way of saying "hate," likely used by people who prefer to avoid the word hate.
The opposite of affectionate is "indifferent" or "cold." It refers to someone who lacks warmth or tenderness in their manner or behavior towards others.