Pig in a Poke Tuesday wrote:
I always thought of it as having to do with halflings being able to slip about unnoticed. Although there is the idea from our own world of a slip of a girl, could be another possible fit.
That was my original thought, too. It doesn't necessarily seem too offensive, but I know that even in our own world, offense doesn't always have to be what word it is, but how it is used.