This term was first used when Sam H had a large quantity of alcohol at a New Years' Eve party many years ago. Sam subsequently spent the entire evening vomitting into a kitchen sink, and followed this by walking home with his head slumped towards the ground. A groundfreak can therefore be somebody who has had too many drinks, but can also be used in a number of other situations. For example, if an individual is wishing to be alone for sustained periods of time, or becomes reluctant to participate in certain activities, they can be said to be groundfreaking. Furthermore, a groundfreak can be a person who is upset, tired or complaining a lot. The term has become somewhat of a cult saying in British universities.
I'm not sure what's up with Nathan, he's being a groundfreak.
Matt isn't coming out to play football today, he's groundfreaking.