Slowly, the term reveals itself as an expression of fundamental tensions and deep structural antinomies: between the sacred and the profane, purity and impurity, morality and immorality, cleanliness and dirt. In conjoining such primal opposites into a single category, white trash names a kind of disturbing liminality: a monstrous, transgressive identity of mutually violating boundary terms, a dangerous threshold state of being neither one nor the other.
Source: wiktionary