Is 'border-jumper' a racial slur?

No word, term, or phrase is in itself a racial slur, but any word can be used as such if it is intended to denigrate, belittle, or malign another based on ethnicity. Words are amoral, and have no life of their own. They require intent, context, and delivery to be anything other than an abstract representation of concrete things and ideas.

So, "border-jumper" can be a racial slur if it is delivered in a context meant to castigate another based on his ethnic origin.

The actual term "border-jumper" literally means a person or thing that leaps over a boundary, and has no negative connotation other than what it is put to.