Lawful Good - A lawful good character typically acts with compassion, honor and a strong sense of duty to the lawful officials and justice. A lawful good character acts as a good person is expected or required to, with the discipline to keep the law. He tells the truth, keeps his word, helps those in need, and speaks out against injustice. A lawful good character hates to see the guilty go unpunished, but may be conflicted if the law requires them to take a side they might not believe in. (Superman, Captain America)
"It is my duty to uphold the law with truth and justice"
Neutral Good - A neutral good character does the best that a good person can do. He is devoted to helping others and stopping injustice in the world. A Neutral Good character is guided by his conscience and combines a commitment to oppose evil with the discipline to fight relentlessly. They do not fight for themselves or a higher power, but to protect innocents. A Neutral Good character has no problems with co-operating with lawful officials, but does not feel beholden to them. Has a strong sense of what's right and wrong. (Batman, Spider-Man)
"What you are doing is evil, and I will stop you because it's the right thing to do"
Chaotic Good- A chaotic good character acts as his conscience directs him with little regard for what others expect of him. He makes his own way, and acts as an antihero. He believes in stopping evil, but has little use for laws and regulations. He follows his own moral compass, which, although good, may be violent and often out of alignment with how society would want them to. But they will fight for what they believe in, and give no mercy. (Wolverine, Spawn)
"No sympathy for the wicked, don't get in my way"
Disclaimer - Not my definitions at all. All definitions go to the internet.