A romantic association between two people where one or more of the parties involved refuse to call it a "relationship", or use the words "girlfriend" and "boyfriend" for fear of attachment or commitment. The behavior of those involved is identical to an actual relationship, except commitments and expectations are not explicit but merely implied. Often defined by social networking sites as "its complicated".
Are you guys boyfriend and girlfiend yet?
No, its more of a quasilationship.