The feeling of being high or beyond happy, often to the extent that one becomes deaf to anything outside their own head. Always used on girls, as any guy described as being 'floaty' would be considered gay.
Lily was all floaty after Ryan asked her out - I had to scream in her ear before she realised algebra was over.
Sara expressed her true fossyness when she tickled Chris for having eaten one of her cookies.
When one wishes to impose a playful frustration, verbally admitting one has become fossy or possess fossyness portrays a humorous irritability within that person.