A person that does one or both of these 2 things:
1) turns up at an event mainly a party without getting invited by
the host(s).
2) Asks
the host if they can come to an event,
even though it's invite only and they weren't invited in the first place. *
* this puts the host in an awkward situation where they have to say 'yes'.
Person 1 : hey isn't that
Toby over there. Did you invite him?
Host: yeah it is. I didn't ...
FfsSelf inviter: hey Sarah ,
heard about your party is it ok if I turn up?
Host: urm.... Sure I guess.