Rancor is defined as bitterness or resentment. It is spelled rancor in the US, and rancour outside the US.
The adjective form is rancorous, while the adverb is rancorously. These forms are spelled the same everywhere.
It of course also left “a legacy of political rancor and racial hatred so intense” that it guaranteed the world war that would follow 20 years later, which by Keegan’s calculation was five times as destructive of human life. [Wall Street Journal]
Actually, we owe our gratitude (or rancor, depending on your perspective) not so much to what the Sixers have done over the past two seasons, but to their honesty about how they’ve done it. [Bleacher Report]
The rancour has split ASEAN, with several states including some of the claimants reluctant to antagonise Asia’s economic giant. [First Post]
Rancour over Nasri’s exit has not disappeared with time at the Emirates and the midfielder is prepared for more verbals at Wembley. [The Guardian]
It is the latest in the long and rancorous debate over whether automatic traffic violations are about safety or revenue for cash-strapped cities and municipalities. [Washington Post]
The BTUC is firmly against plans for outsourcing or mutualising services, declaring in the aftermath of the rancorous town hall meeting that it would fight Government “every step of the way”. [The Royal Gazette]
With these two albums, Prince returns to Warner Bros., the label where he made his Eighties classics, then rancorously left in 1996. [Rolling Stone]
The Sex Pistols released one album before rancorously disintegrating in 1978. [The Telegraph]