A. To have or to possess a degree of couth.
B. A Paladin playing World of Warcraft who never listens to his group members because he feels above them skill and experience wise. He often queues for random dungeons with a tank and said tank leaves group upon joining. Ironically Couthful is usually the best player in the group by far, able to lead and outdamage everyone, however his name seems like antonym for himself.
A. That was couthful of that dude to hold the door open for his girlfriend.
B. "Oh crap!" he yelled, "Couthful is in our group, he is going to quadruple the damage I do then sarcastically belittle me with backhanded compliments! :("