2.) In fanon it is someone who is mischievous, impulsive, and selfless as well.
2.) Harry: I was trying to help.
Draco: You didn't consider the consequences and now you're ruined everything! Stupid Gryffindor!
3.) Aw, you were a real Gryffindor when you got your needle, Jim-Bob.
One of the four 'houses' at Hogwarts.
Usually consists of the bravest and true students.
Their mascot is the lion.
~Taken from The Sorting Hat's New Song (OotP)