There are two ways to define 'Skinny
Love', but both talk about romantic relationships.
The first is used to describe a type of relationship between two people that are very in love with each other, or are crushing big time on the other; but are far to embarrassed to express their feelings. The relationship is 'skinny' because they have yet to come out and explain their true feelings. There is no communication,
there for it's not even really a 'relationship'.
The second is to describe a similar thing, but instead of no communication, the relationship lacks love. It is where two people are dating just for the sake of dating, the sake of being with someone. To fill that empty void, to give them
something to do. They do not actually love each other.