Spite
Etymology
A shortened form of "despite," from Old French "despit," from Latin "despectus," “a looking down on,” from "despicere" (to look down). Spite began as contempt or scorn and hardened into active malice. The clipping happened early, leaving “spite” and its parent “despite” to drift into different jobs.
noun · /SPYT/
The desire to hurt, annoy, or thwart another even at cost to oneself.
What it names
Reach for it for the self-defeating grudge — harming your own interests just to deny someone else a win.
Example
He sold the house below market value out of pure spite, just so his ex couldn’t have it.
Related idea
Against ordinary malice: malice simply wishes another harm; spite is the peculiar version willing to pay a price for it — the “cut off your nose to spite your face” logic. Game theorists study it precisely because it violates self-interest: the spiteful player accepts a worse outcome to make the other player’s outcome worse still.