1.)In Harry Potter canon it is someoneone who's brave, daring, chivalrous, and has nerve.
2.) In fanon it is someone who is mischievous, impulsive, and selfless as well.
1.) Harry was sorted into Gryffindor because he was brave.
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.
When you've been working like a house elf (crazilly hard) and are done for the day. You are free. Master can represent professors or bosses, and Dobby represents the overworked person talking.
The phrase is from Chamber of Secrets by JK Rowling.
Chris: Are you done classes today?
Trudy: Yeah, I'm free. Master gave Dobby a sock.