Wiktionary
interj. 1 (context slang English) goodbye. 2 (context slang English) go in peace. vb. 1 (context intransitive English) To become unconscious; to pass out. 2 (context transitive English) To render unconscious. 3 To experience an altered state of consciousness. 4 (context intransitive slang English) To depart.
Wikipedia
"Peace Out" is episode 21 of season 4 in the television show Angel.
Usage examples of "peace out".
He had to believe that Adica and the other Hallowed Ones knew a way to coax peace out of conflict and hostility.
I have to be vigilant against what I am -- for if I'm not, who else will make peace out of this horror?
That woman over there will be my wife and you but a concubine because this is a political thing and we must weld peace out of this moment, enlist the Great Houses of the Landsraad.