边缘性 is an abstract noun meaning 'marginality' or 'peripherality' — the quality of being on the edge or outside the mainstream. It is commonly used in social sciences, psychology, and political discourse to describe marginalized groups, peripheral areas, or the condition of being at the boundary rather than the center. Note that the English gloss 'marginal' is an adjective; this word is strictly a noun, so it fills syntactic positions like subject or object.