Ligger
/ˈlɪɡər/
Definition 1 of 1
Pro Tip 1/3Often Unwelcome
Liggers are not usually welcomed since they attend events without an invitation. 
The hosts were annoyed to spot a few liggers at their exclusive gathering.
Pro Tip 2/3Sneakiness Implied
The term 'ligger' often suggests someone who is sneaky or takes advantage. 
He was known as a ligger, slipping into movie premieres unnoticed.
Pro Tip 3/3UK Specific
The word 'ligger' is predominantly used in the UK, so it might be unfamiliar elsewhere. 
When I used the term 'ligger' abroad, no one understood what I meant.