Yeah, that's the fancy word to define quite argumentative and uncooperative people. Yes, these people do exist and somehow manages to get into romantic relationships. Some people become one, during the relationship but some people are too particular regarding this grumpy trait and they let their partners show their real side before getting into a proper relationship.
First and foremost, no one likes to date a fighter cock and no one likes to imagine being in a relationship with someone who always needs something to pick an argument. But that doesn't mean one can't fall in love with such a person and if you are a person who likes the crankiness in your partner, then you must appreciate your patience levels. If you treat this particular trait as just one of the characteristics of your partner, then you can be happy in your relationship. But if you completely focus on the aspect of bad temper, then it becomes difficult especially when you face a few extreme situations.