renege
UK: rɪˈniːɡ | US: rɪˈniːɡ
vi. to go back on a promise, agreement, or commitment
vt. to revoke or deny (archaic, less common)
The word "renege" originates from the Latin negare ("to deny"), combined with the prefix re- ("back"). It entered English via Medieval Latin renegare (to deny again) and Old French renier. Initially used in card games (16th century) to mean "refusing to follow suit," its meaning expanded to general betrayal of commitments. The morpheme nege preserves the core idea of denial, while re- emphasizes reversal.
He reneged on his pledge to donate half his wealth.
The company reneged on its contract, causing legal disputes.
Politicians who renege on campaign promises lose public trust.
She accused him of reneging on their informal agreement.
In card games, reneging is considered a serious foul.