To "Agnew" is to laugh at a private joke, which you are not
part of.
Different uses:
To agnew, to have agnewed, to be an agnew,
epic agnew
Sam: Remember that
time me and you were in Mikes
car and rolled up on that dude and that underaged girl making
love?"
Oli: hahaha, we weren't afraid to hit people in the face
Rob: hahahaha
Sam: Rob, you just pulled a total agnew